97 maxima has been having acceleration and idling issues. takes forever to accelerate, pressing the gas hard doesn't give nearly as much power as it should and it idles at around 1100, fluctuating up and down a few 100's. even stalled a time or two. cleaned the MAF and throttle body, threw in a new air filter, still happening. took it to a shop and he said it was either the MAF or a clogged cat converter. i'm 95% sure it's not the MAF because I cleaned it yesterday (MAF cleaner) and it looked pretty shiny and good, no permanent build-up or debris on it. throttle body looked good too. also the exhaust sputters a little liquid out of the back, so that's all the more reason to believe it's cat/exhaust related. whats the best way to go about this, or is buying a whole new cat converter my only option? is there a way I can test to know that's the problem before I go out and buy a new one? heard about seafoming too.. is that possible? thanks..

 

you can't seafoam away a bad catalytic converter.

In my Pontiac, you could test for a bad cat by drilling a 3/8" hole in the exhaust pipe in front of the cat. Start the car up and if the idle is smoothed out, then clogged cat is your issue. If not, then throw a 3/8" screw in the hold you drilled and you're done, and can go to something else.

^^not sure if same method is OK or recommended in our maximas, but it's an idea.



Are you SURE you have no vac leaks? Those cause rough idle and can cause hesitation. And just 'cause MAF "looks good" doesn't mean it IS good.

 

If you need one, I happen to have one for sale.

 

It's easy to check for a clogged cat.
1) Remove cat
2) Look inside, if it's plugged up replace it. If you can see through the honeycomb, it's ok.

 

is there a step by step guide on how to remove the cat?

also is there any way i can check for vacuum leaks at home?

oh by the way I ran the car with the MAF unplugged, it stalled trying to rev. so that rules out the MAF doesn't it?

 

Remove the bolts to take the cat off. Your maf is fine

 

for a lot of people, they cant just take the bolts off to the cat. most of them are rusted together like all hell, making that a bigger pain in the ***.

 

PB Blaster

 

In my ford pickup computer throw code. I cut out old cat and both one for 75$ at internet. Install with band clamps. Worked good, and good still today.

 

no. im talking about bolts that need to be ground down and punched out.

 

Check your wiring to the MAF. I had a similar issue on my old max and after spending about $600 at the mechanic, I back-traced the sensor wires and they had become so brittle that the only thing keeping it slightly working was the shroud around the wires.

 

you mean the thin wires inside the MAF..? because they look healthy. maybe i'll take a pic and post it this evening. if not, i'm not sure which wires your referring to

 

I'm referring to the outside wires that run to the MAF sensor, not the MAF itself.

 

here's the wires to the MAF. look pretty good to me? (and before anyone asks, yes it's been plugged in this whole time haha).. they're supposed to be interconnected like that in the second pic.. right?






by the way.. if i were to get a MAF from a junkyard to see if maybe the MAF is actually the problem, do all 95-99's have the same MAF or do I need a specific one for my year? (97)

 

same.

Wires look good to me, but are they loose inside the connector?

 

Was the engine holding RPM's and running fine (w/o revving) while the MAF was unplugged? If so, that is a strong indicator that your problem may lie with the MAF. I recommend testing the connector like Amerikaner is hinting towards. If it holds RPM while disconnected but not while connected, I would focus here.


Seriously??? Very helpful post.

 

Yeah seriously. If the problem is still around with and without the maf still plugged in, that rules that out like he said. If its a small problem, sure it could make a difference. I looked in the Haynes manual for all his problems, they all have something in common: Obstructed exhaust system, emission control system not functioning properly, fuel filter clogged and/or impurities in the fuel system

there also might be an intake leak between the tb and the intake mani (op did you replace the gasket when you cleaned it?)

OP: is your CEL on? I can only assume not since it wasn't brought up. if it is, what codes is it throwing?

 

I'm apologize for coming off so condescending but I really hate it when people throw out words as fact without giving any backing evidence. Thank you for clarifying your opinions.

And the MAF has not been ruled out just yet. He said that the engine died WHILE revving with the MAF disconnected as it should. However, if the engine holds rpm WITHOUT revving then it points towards the MAF.

 

The car usually idles at around 12-1300, slowly decreasing to around 900. I unplugged the MAF while it was running and it sounded like it was about to stall, but it came back to life and kept running. Idle stayed at around 900, solid. Also what's your way of testing the cable? Again they *look* perfectly fine, wiggled them around and tapped the MAF sensor while it was running and the car was unphased by that.

I also should note that the first startup is almost always rough. sounds like it's choking and barely going to start, and then it starts up. any start ups after the first one are basically smooth and fine.
nope didn't replace anything, just took it apart, sprayed MAF cleaner on the MAF, let it air dry, put it all back together. *however* i noticed when i rev the engine with my hand on the throttle under the hood, after reach rev, I think I can hear the butterfly flap flicking around for about 1 second. rev, *butterfly flapping sound*, rev, *butterfly flapping sound*. lasts for a second and then goes away. i'm thinking maybe the whole throttle body needs a cleaning?
the "service engine soon" light is on, yes. i can't check for codes though as the car isn't insured right now so i can't really drive it to a mechanic (legally) to get it scanned.. any other ways I can diagnose the CEL?


here's some pics I just took of the exhaust. notice the small tear deep inside the tail pipe.. doesn't look like something that should be there lol. also, that leak on the floor under the tailpipe was what leaked after just 3 minutes of the car idling. so clearly there's a leak problem there.

 

I would try to take it to the local auto shop and ask them to diagnose it. It kinda looks like oil inside there. But it could also be dirty. I really don't see oil getting in there unless someone pours it in there.

Did you crack the gasket by chance? Mine was very brittle when I did mine

 

nope didn't crack it that's for sure..

 

If you go in the 4th gen how to section it will show you how you can pull codes directly from the ecu.

 

Manual code check:
1) Remove the plastic cover the right of the gas pedal and you will see a screw on the back-side of ECU.
2) Turn the key to the "On" position w/o starting. (Check engine light will turn on)
3)Turn the screw all the way to the right (Does not make full rotation so don't force it)
4) Wait 2-3 seconds, then turn screw back to the left.
5) Check engine light will begin flashing - Long blinks followed by short blinks.
6) The long blinks represent the first two code digits, the short blinks are the second two (7 long, 7 short = 0707)
7) If you have more than one code, it will follow in sequence, then after the last code, it will repeat over again.
8) To clear the codes, turn screw to the right again, wait another 2-3 seconds, then turn back to the left.

 

Now we're getting somewhere.

 

thanks for all the help guys. i'm going to clean the throttle body and check for codes and post the results ASAP

 

Well I just went to do this and on step 2 and the check engine light didn't come on. i remembered that it usually comes on after the car starts up. that's when it shows itself. so i went to start the car and then shut it off and then go through your steps again. the car doesn't start anymore. this has never happened. chokes and struggles quietly for a second and then nothing.

 

Put your key in and turn two clicks, should be on "acc"

Does the cel come on then?

 

the CEL doesn't come on whether it's ACC or ON

 

Man. One problem after the next lol.

Your bulb isnt working. Could be burnt out. Could have a loose connection idk.

 

any chance of a battery problem?

 

If other lights come on, no.

 

If the other lights on your dash come on but the MIL light doesn't, chances are it burnt itself out. Not uncommon on an older car. Remove the dash bezel (two screws on the top), then take out the gauge cluster (three bolts, one top/two bottom), to test it you can just swap the bulbs out with one you know works. from there you can repeat the test.

 

Call Warpspeed for a new flanged high flow cat.....

 

I haven't switched out the bulbs yet (been pretty busy and it's blazing hot.. not a comfortable task to perform in a confined, leather-seated car lol..).. the car still doesn't start. but about that pic I posted with the whole inside the exhaust.. would that not be a sure-tell sign of the problem, or can the car still operate normally with that..?

also what are the chances of the fuel pump as an issue..? when i bought the car used and took it home I found a fuel pump in the trunk, looks like it's in pretty good condition.. maybe the one in there right now is bad and the owner never got around to replacing it? (it was a female, go figure hah). because my fuel gauge is inaccurate too, it always says the tank is at half when I park the car and shut it off even though I know it's almost empty.

 

I also just noticed my electronics are slow..e.g. my windows go up and down slowly and on the highest speed my wipers move very slowly too