I’m having some serious issues with my daily driver Max. It started out as a starting problem. Let's call this Stage 1. From one day to the next, the Max developed the longer cranking syndrome before it would start. This went on for about two weeks but the Max still drove fine once started.

Then the problem evolved a little. Let's call this stage 2. In addition to the longer cranking, it would stumble and idle funny for about 5 seconds after it started. After that 5 seconds, it idled fine and drove fine. This lasted for about a week.

Now it’s un-driveable. In addition to the two problems above, now the idle is really rough, and after 10 minutes of idling, it will start to sometimes backfire (small and subtle, not violent nor loud) and billow white smoke out the exhaust.

Background info:
1998 SE, Auto
Supercharged about 10k miles ago
All maintenance up to date with install of supercharger. New NGK copper plugs, fuel filter, PCV valve, cleaned TB and IACV
Currently has 230k miles

I checked the fluids and they’re all full and look like they should. No codes. At the first two stages, I had some hunches of what the hell was happening, but now I’m stumped and very concerned and dreading the worst. I don’t want to throw out my ideas and thoughts just yet as I don’t want to influence what you guys say.

Any input or advice would be most appreciated. Thanks.

yes, but doesn't it always rain in southern California?? billowing white smoke, any overheating?? my max stumbles out of the gate when really cold, but if i let her warm up for a few she's fine. check your: 1. coil packs, 2. maf 3. anti-freeze for leaks and go from there. if you were anyone else i'd throw a few more suggestions out there, but im sure your as thorough if not more so than me.

Makes me think CSPS, but no codes..

Sometimes the ecu isn't always quick to pick up codes. In regards to white smoke and subtle stumbling maybe check injectors. Possible o ring cracked or deteriorating letting in too much fuel??

I had a very similar issue and it turned out to be a fuel injector. The little plastic pintles on the end dry out and I guess it was stuck open. When I took the fuel injector out that pintle was cracked so it wasn't staying on the fuel injector like it was supposed to. This was causing the engine to be overflooded with fuel and caused rough idle, white smoke from exhaust, idle/stalling problems. If your oil does not look milky and your not losing coolant into the oil I wouldn't think it would be the head gasket. Is your check engine light on? Even if it isn't have you scanned for codes?

Mine was one of the back fuel injectors so had to remove the UIM which isn't very hard but if it's a front one that it is extremely easy.

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ac max 92 beat me to it

Sounds like a blown head gasket. They don't always cross contaminate fluids. Have a block tester (green fluid) put on it. It might be a small leak in the gasket between the water jacket and cylinder.

Mr. Wizard, say it isn't so???? Does sound like HG, but the back fire isn't a symptom of HG failure. Pull the plugs and see what they tell you. Unplug the MAF and see if it idles ok in limp mode.

No overheating issues. Coil packs and MAF are definitely possibilities.

You reminded me of something. Back when my problem was minor, let's call it stage 1 or 2, I changed my oil. During the oil change, I decided to clean the CPS since it had 15 years of gunk build up around it. I uninstalled the CPS and gently cleaned it, and only allowed a soft rag to touch the actual sensor. No chemicals were used.
I suppose anything is possible. But wouldn't too much fuel billow black smoke out the exhaust meaning I'm running too rich? I have white smoke coming out the exhaust.
Thanks for your input. Sounds like you and me have similar symptoms. What's weird though is that if the engine is being overflooded like you mention, wouldn't I be getting black smoke out the exhaust (not white)? But maybe you're on the right track though. See my new info below regarding the coilpack. Maybe the injector issue you're suggesting is triggering the coilpack code?

That was my first thought too but these engines are pretty damn tough and I haven't done anything out of the ordinary to cause the HG to blow. I have not ruled this out as a possibility though.
Thanks for your input too. I haven't pulled the plugs yet to see what story they tell, but today I unplugged the MAF like you suggested and it started and idled. Idle wasn't any better or any worse. Still rough.



New info: Not sure if this is a clue or not.
Recently, the Max finally threw a code for a bad coilpack while idling for a few minutes the other day. Coilpack #1. I swapped it with another coilpack out of another Maxima. Only minutes later, the same coilpack code came back!! Is this a clue, or is just random crap just happening since it's idling rough and it means nothing?

Another piece of info that I figured I'd share but not sure if it's relevant. I have several boosted Maximas. When the hood is open and I turn the key to the ON position on the perfectly running Maximas, I can clearly hear the fuel being primed. I can't remember if this fuel priming sound was/is on this problem Maxima when I SC'd 10k miles ago, but it definitely doesn't have the same distinct sound my other Maximas demonstrate now. Would a bad/weak fuel pump explain my problems in all of its stages? This was my first hunch. With the white smoke coming out the exhaust, I was thinking that maybe I'm running lean?

Maybe even a bad FPR? Before the white smoke started and the car was driveable, once the car started and drove, the next time I started the car within a few hours it was totally fine! If more than say 4 hours went by, then I'd have the problems I described in the original post.

see if it starts quick with starter fluid - if so that should eliminate the cam and crank position sensor

sounds like a headgasket issue to me,

stage 1 was beginning, a bit of coolant in the cylinder, would start once it was cranked for a bit and the coolant blew out or spark plug was able to spark the fuel, then the car would stubble till all the coolant was all out of the cylinders and run but now your at the point that coolant is going in just as fast as it is burning

best way to check is to pull out all the spark plugs and check if there is white stuff on the tip, that would be coolant, if not, take a borescope if you have one and check if any cylinders are wet

All fluids were fine, and it's not drinking coolant?

This might be the problem. I have a 01 thats supercharged and i had that same problem Minus the extended cranks to get it started. My issue was after i would start it (cold start) and leave it idling it would idle super rough, my AFR would lean out all the way, start to backfire a bit and forget drivability - I couldn't even drive it cause it would stumble, backfire etc.

So i checked fuel injectors and one O ring was leaking a bit - so now im thinking BAM got it. put it back together a still the same crap. checked plugs, coilpacks, etc. NOTHING still same thing.

At this point im like what else could it possibly be!, and now to my fix. I always wanted to change out the STILLEN FMU that came with the kit with an adjustable one to kinda fine tune things the best i can. So I did that and WALA problem fixed. I guess the Stillen unit had some clog in it that was restricting fuel from initially getting to the motor the first minute or 2, or until warm up and cause it to run lean causing this issue.

Hope this helps.

I would strongly lean towards the fuel pump since you can now hear it. Another fuel pump test would be to drive it on the highway, and in 4th gear, at around 60 to 70 mph, accelerate hard. If the car acts up then your fuel pump is definitely on its way out.

If your FPR has never been changed before, go ahead and replace it. It costs like $5. A bad FPR in my car caused hard starts and backfires with sudden acceleration on the highway. Once changed and the car started like a champ and backfires were history.

are you guys discussing the problem I have with 97 max & 04 Infinity? While idling or stopped at light, I feel a light "thud", thud sound fron engine as though it might stall! Recently changed all the spark plugs. No codes & CE light. It is not continuous thuds. Like couple of times every 2-4 minutes. Any help is greatly appreciated. If it is mis fire how to identify the problem coil and or the SP?

Fuel injector 100% garunteed. It had happened to me and same symptoms that u were having I had.

What's strange, is the last 5 times I've started the car, it's fired right up no problem. Just have the rough idle and white smoke out the exhaust lately. I'll keep that in mind if Stage 1 or 2 come back.

Well, I hope it not the headgasket, but we'll see. When I bought the Maxima 6 years ago, it had Stage 1 and 2 issues. I fixed that easily by cleaning the TB and IACV and it's been fine ever since until recently.

I'm going to pull the spark plugs Friday and see what they look like.
Correct. I'll check them all again Friday and see if anything has changed.

It does help, thank you. I probably would have never thought of that. Checking the FMU is free and easy. I have some spares too if need be.

I explained the Fuel Pump sound poorly. I went back and rewrote my post. You have it backwards. I should be able to hear the fuel prime when I turn the key to the ON position and have the hood open. At the moment, I don't have that familiar sound. My fuel pump isn't making any sounds.

Thanks for the info about the FPR. I have some spares laying around and may just swap it out for another.

Thanks for your input. I'm getting quit of few people saying fuel injector. Also, as I eluded to before, I'm recently getting cylinder 1 misfire codes, even with a known recently installed like new coilpack. I'm thinking it is a big clue after all.



Today, I bought a block tester from NAPA and will test for a blown headgasket on Friday, as well as check out the sparkplugs and see what story they tell. After that, I'm torn if I should rip off the manifold and check/swap the injectors (specifically #1) or swap in a new FPR and fuel pump.

Check the Maf......Mine wasn't the exact same as yours but had some of the symptoms you have. I bought one from ebay and the damn car roasted the tires! haven't had the problem since.

That's easy.....since the fuel pump, FPR and injector are all inline with each other, do the cheapest/easiest one first. One of those is probably affecting the other anyhow. You can do the FPR without removing the manifold....at least on a 98 VQ motor you can. Right there next to the PCV which you may as well replace too, as well clean the TB since you have to remove the airbox and stuff around them to get some decent working room.

How did you solve? Replace all injectors or a particular faulty one? How to determine the faulty one?

I got used OEM injector rail from ebay with injectors and replaced the whole for 100.00 by myself. This car is super easy to work with. You can replace the front 3 injectors by getting some used ones from a low milage car like I did and see if that helps u.

thanks a lot for the good tip. do you think it is worth cleaning the injectors as some YouTube items demonstrate?
has any one done it & with what results? i mean effortwise.

Please stop thread jacking my thread and start your own thread if you're having issues. Thanks.

the truth is fuel injectors don't really get dirty or that dirty at all because the quality of gasoline is really superior with a lot of detergents that already keep them clean. The fuel injector mechanically go bad and theirs no other option but to replace them. If you do replace them and get new ones I recommend that you use premium gasoline in your car which is the highest quality gas available and will keep those injectors clean and running good and will provide better performance as well for our VQ30de engines.

Quick note, driving a car with a bad fuel injector will makes things worse and make cause some sort of engine or cylinder damage. Be careful and get it fixed.

Injectors get dirty at the tips with carbon from the pcv system. Premium fuel is not the highest quality gasoline, it is the least prone to detonation and has the least amount of energy/burns slowest.

I have some news today.

HG test passed.

Pulled sparkplug #1 first, and was amazed at what I saw. Also, it smelled really really strong of gas.

Pulled sparkplug #3 next. Looked ok, only a very faint smell of gas.

Pulled sparkplug #5 next. Half of it looked ok, other half was as bad as #1. Moderate smell of gas.


In the pic below, they are in order: Sparkplug #1 (left), #3 (middle), #5 (right)


Also, I'm missing my pintle cap from injector #1!! I looked down in the head and can see it!! Not sure if it came off when I removed the injector, or it's been there and is the cause of my problem. When the intake and exhaust valves open, how much do they open?? Would the pintle cap fit and fall down? Or is is stuck there until I remove it? Anyway, tomorrow I will remove the LIM and extract the pintle cap.

I also pulled injector #5 for comparison. The pintle cap was attached, but has a split in it. Looks like I'll be ordering 6 new pintle caps. Probably get new o-rings and filter screens as well. I'm deciding whether I should throw in my six other used injectors that I pulled off my beast Max when I went 555cc's, or just get these injectors cleaned and rebuilt.... I have my other six injectors in a ziplock bag, but I din't oil them for long term storage as I should have according to my research tonight...

Injector #1 (left) with missing pintle cap, Injector #5 (right) with cracked pintle cap

told you bad fuel injectors. I would get some good used ones from picknpull and there only 6.00 each. I got mine from a nissan maxima with only 141,000 miles and they were brand new with the pintle caps still in brand new condition. Sometimes you will get lucky and get good parts like that. Or try junk yards. But there could be a chance that those fuel injectors could be bad.

Yep same exact thing happened to me, pintle cap fell off. Once I replaced that pintle cap problem was gone

how the heck do pintle caps fall off? Arent they mechanically coupled?

Also, i pulled some fuel injectors from the junkyard. was I supposed to grease them or something for long term storage?

They get brittle and eventually just crack and in some cases fall off. All mine were cracked but only 1 of them fell off.

Well, I'm not of the woods yet. Like I said, I'll never know if the pintle cap fell off during removal of the injector (probably) or not.

You should have mentioned that from the get go! Were you able to extract the pintle cap from the head or did it disappear past the valves?


I still don't know if the pintle cap is my source of the problem, the injector, or both. Maybe neither. Won't know for sure until it's back together. I sent out my injectors today to Deatschwerks to be tested, cleaned and have new o-rings, filter screens and pintle caps installed for piece of mind. I extracted the fallen pintle cap out of the head today.

More pics of the carnage...

Cracked pintle cap and missing piece


Out of the 6, no pintle caps were intact w/o cracks and/or missing pieces.


I'm starting to think that servicing injectors at 200k miles should be mandatory.

Good idea. Would a proper service mean replacing both O rings, the filter and the pintle cap? Or would there be more to it?

Yeah I was able to retrieve the pintle cap. If I remember correctly it didn't fall all the way down it was kinda sitting near the top. The other injector pintle caps were missing tabs or cracked as well but still hanging on there and I couldn't be without my car for a week while I was waiting on the new pintle caps so I jsut found the best looking ones I could from pick n pull and put those in. So far so good but I should probably replace all those since they were cracked and I have new ones just sitting here now.

Good work, hg was a big scare. I sent my top feed 440's to withchunter even though they came out of a terminator cobra and looked new. I didn't want to kick myself down the road.

i had those same symtoms * changed out the fuel pump fixed 80% of the issue then the sending unit with of course new screw and gasket .. The problem was getting worse and gas mileage was becoming horrible ... But stuttering starts to having to hold the gas pedal down etc.. Sounds like the same symptoms to me i hope this helps...

Also i have been using sea foam, and fuel injector cleaners to help

Well, that's about half of it. Injector cleaning services claim you can potentially gain 1-2 MPG's by having your injectors cleaned/serviced. I suppose if your MPG's are good, and your having no fuel related issues, then the o-rings, filter screen, and pintle cap on each injector should suffice for maintenance. Kits are sold on ebay for a reasonable price, especially since pintle caps and filter screens are not sold separately from the dealer.

Yup, better safe than sorry...especially on boosted vehicles.

My car is pretty much on or close to OEM mpgs, and I'll stick with my injector cleaning regimen: heavy footed highway jaunts and TCW3. It's more fun too

Check your Water temperture sensor it will prolong a cold start and run fine with a slight hunting effect at idle..... Be sure the 5v signal is making it to the sensor and the return wire has continuity to the ecu....

Update time...

Got my injectors back from cleaning/servicing



Looking at the Pre-Test results, two of my injectors were leaking under pressure. Variance was a little off at 4.1%



Final results after cleaning/servicing. Variance within 2% and no more leaking!