96 I30

Sometimes bogs and stalls, mostly when the car is warm, but not always. I do smell the sulfur rotten eggs sometimes, and occasionally a little fuel.

The CEL is not on, and there are no codes stored, no codes pending. The catalyst monitor is not ready and has not been ready in at least 2 years due to the drive cycle for it being impossible. All other monitors are ready.

I know a bad cat can cause some of those symptoms, and can also cause the readiness monitor to be even slower than normal, and that is on top of the 4th gen Maxima being a slow system already

 

I'd say that your car has one or more leaking fuel injectors.

Its possible that the cat has been ruined.

A leaking injector often does not set a code.

 

Oh man that sucks! Especially if it's one of the rear injectors! (1/3/5)

I replaced Injector #4 a few years ago. Thank goodness it was in he front row so easy to get to. I bought a Bosch injector, which is a reboxed OEM unit. When it went bad, the P0304 code was present. And it was misfiring constantly and obvious it was no good.

I need to get another car! This one has too many miles and way too much rust!

 

Consider that your car is the devil you know.

Another car is the devil you don't know.

It will have issues as well.

You might want to shop for a car from states where rust is rare.

 

Having this issue right now...sucks, but I believe the Catalytic converter is shot after all the raw fuel was dumped when mine was stuck open... idk.<br /><br />If it has rust issues, it's best up to you what to do. Where I am rust is very rare so i'd take J V G's advice..

 

now that's a bad cat!!

 

You can also open the flange between it and the Ypipe and visually inspect it's forward inlet side!

 

Some years ago I had cooked and clogged cats.. After spending a bunch of money for multiple misdiagnoses, I had the car towed home from the dealer. In my driveway, I jacked up the car and removed the O2 sensors from the exhaust manifold bungs so the engine could breathe. I left the O2 sensors plugged in. I took a couple of zip ties and secured them so they wouldn't get damaged from dangling while driving. Next I started the car and took it for a drive. It ran good. It turned out I had leaking injectors that ruined the cats. If leaking injectors allow the car to run too rich for too long, eventually get roasted. I installed a Warpspeed-Y pipe and eliminated the cats.

 

Damn so I may have a converter issue being that I ran too rich for too long due to the leaking injectors... Recommend that I should replace it with a Warpspeed Y-pipe?

 

The Warpspeed thing is only the pre-cats, which I believe don't affect things too much.

The main cat itself is only $100 and probably not too difficult of a job, and even if I paid someone to do it still not too expensive. But even that is more money than I want to spend on this car.

And the y-pipe is over $200, much more than I want to put in to this car. The fuel injectors, especially if they are the rear, are impossible to do. Magnaflow makes a good y-pipe with the mandrel bending while retaining the pre-cats.

I just wish it would throw a code already! If it can tell me which cylinder is misfiring, then I can replace that injector only and be ok, if it is #2 or #6 (I already replaced #4, remember)

 

The precats do affect things..

The main cat is probably rusted on if original..not usually DIY unless you're torching or cutting yourself..

A warpspeed y isnt that expensive; the cheap route would be to remove your y and hollow it out..no point of getting a y with precats if you're not looking to replace/check the injectors, because if it is a leak you'll just toast those new cats too

The rear injectors are no where near impossible..just an UIM removal

 

FJF above is right, there are details that need attention.

Sounds like you have a Cali spec'd Max. Is this true?

Much of the exhaust system is different between Cali and Fed spec. Mostly between the exhaust manifolds and rear Cat. Along with the differences in O2 sensors. Then there's the pipe between the rear cat and resonator. The Fed spec has a sensor port pipe piece with a shorter resonator pipe, and the Cali doesn't and the resonator pipe is longer.

Then there's the matter of which state you live in and how strict their Inspection process is.

I live in NY and their policy is STUPID STRICT and now requires nothing but CARB compliant components and no bypassing any sensors. Repair shops installing anything but CARB compliant and/or doing illegal Mods get fined heavily. And I have a Cali spec 99 SE. My exhaust is trashed and flex pipe is shredded. The Magnaflow SS Y-Pipe (two pre-cats) and Rear Cat is over 1K alone, then add sensors.

Whatever you buy, make sure they are fitted with welded flanges and not straight pipes. Bosal also makes great stuff and usually more reasonable when shopped. But I'd prefer Magnaflow's top of the line Stainless mandrel bent exhaust components. Then there's the whole Cat Back thing. OUCH.

But most of all, pay attention to laws and what it takes to getting your car inspected so it will pass. Then make decisions that work for you.

AND.... Doing Fuel Injectors has a bunch of steps but is nowhere impossible to do. In fact, it sounds like you are overdue. I wouldn't touch the exhaust until I replaced all the fuel injectors properly. Anybody who hasn't yet, has a higher chance of progressive problems, than not.

Maybe this can help a little, He's got a bunch of 4th Gen Maxima How To's:

 

@KP, yes it is Cali-spec

I have only replaced injector #4 (n the front). The screws were galled, so I had to get a vice grip to remove them. I did get a box of those Hillman screws in case I'd ever have to do it again.

But I have pulled the intake before to replace a valve cover gasket, and it took a long time and was NOT FUN at all! Yes, I call it impossible. Unfortunately, at the time, I did not know about the fuel injector issues these cars have. Otherwise, I would've replaced them a couple years ago when I did it.

 

Once one injector malfunctions due to a cracked pintil cap, assume that the others are about to fail as well. Might as well replace the whole set at once. Doing so means less labor in the long run, as well as preserving your cat.

a new or rebuilt set of injectors might pay for themselves due to gas savings.

 

@JVG yes, I know this now, but I didn't know that when I pulled the intake (this was a couple years ago)

 

Don't feel bad maximaxi, I'm doing my injectors and Fuel Pressure Regulator and new gasket set for my UIM before I do the exhaust as well. Whether I like it or not and whether I want to or not. Even though my Max is worth under $1K, I recently did the LCA's, Struts, Transmission was completely rebuilt, brakes and so much more. What's another $1500 for a few parts with me doing much of the shopping and labor? LOL At least I know what I have and it will be strong for many years to come.

Looking into the best choice for injectors now. Will report back.

 

Sure, our cars are not worth much any more. So some members might be put off by spending 1000 or more for overdue repairs.

Yet if one can have a reliable car to drive an additional 50k miles or more, the cost is well worth it.

it's about not making car payments, or used car payments AND repair costs

 

En How! (remember the "Little Rascals"?) LOL

 

Next time, get one of these screwdrivers. Japanese use a different Phillips shape and these make all the difference:

 

Have you ruled out the MAF?
How do you determine injectors are bad? Would it show on the fuel trim?

 

UPDATE

I think it is probably the MAF now.

I sprayed it with CRC MAF cleaner about a month ago, and it hasn't stalled since.

Thank you everybody for your help!