96 Infiniti J30 Intermittent stalling and stuttering

[wirelessnut]

I have a 1996 Infiniti J30 with 131K miles and it runs a constant 181 degrees cool.

Searched J30 forum for MAF, Mass, Surge AND fail, Surge, Stall, P0100, P0400, others I don't remember.

Symptom: Intermittent stalling and stuttering. If fuel injection didn't exist, you'd swear it was a fuel problem. Seems like sludgy gas or a partly clogged fuel filter. Car runs great until the stall stutter happens.

Codes: P0100 MAF or VAF Circuit failure, P0400 EGR Flow. (Note that I saw a P0100 code like a year ago, but since it didn't cause any driving issues so I didn't take any action at that time except to clear the code, and left it when it came back.)

Pretty much factory original everything. Car has been extremely reliable except for some interior problems related to the harsh Florida sun.

Passenger side headlight (low beam) has a mind of it's own. Works when it wants to. Just found the posts regarding the relay.

Corrections taken so far: ) Cleaned MAF using no-residue aerosol electronics cleaner (Contact Re-nu). Just sprayed the inner sensor housing to soak the sensors, and wiped the outer housing. No cracks in the housing. Cleaned the harness connectors too. After cleaning There was a marked improvement in how often the problem happens and in the severity of the problem.) There is vacuum at the EGR Valve, revved the engine to get vacuum and then pulled the EGR Valve vacuum hose off to snap the valve a few times. No change in engine with the EGR Valve vacuum hose disconnected. Looks like a bear to remove the EGR Valve so I thought I'd best ask the forum first.) Fuel Filter Replaced (maybe FRAM don't remember) when the stutter / stall problem first began.) Ran 1 Tank O Fuel Injector cleaner with High Test Gas. No change.) Just got a round tuit and replaced the radiator, it cracked it during timing belt replacement.

Services performed around 128K:) New Air Filter (Fram) is still pretty clean) Timing Belt replaced following EXCELLENT!! procedure posted in J30 forum at same time as water pump. Car ran like new after. I broke one idler cam bracket on the tension release side (over cranked the tension release heard a crack! - dum, dum, dum), but the tension side was good so I left it in. I don't think this is affecting anything, but I thought I'd better mention it.) New Nippon spark plugs (standard not premium)

Tests performed so far: ) MAF volume increases and decreases according to engine load and acclerator position. It holds fairly steady, fluctuating according to load and road conditions. It's definitely not solid like a rock, and I don't imagine it's supposed to be.) Tapping the MAF produces no change in engine's mood.) Throttle position sensor appears good, responds normally.) There is vaccum to the EGR Valve, but I haven't verified if the valve opens or closes and I haven't removed it to inspect / clean / replace.

At it's mildest:While under load, the engine will just stall for a split second and go on like nothing happened. It's like your heart skipped a beat. A P0100 event and / or a P0400 event will be logged.

At highway speed:Tries to stall, you put the car in neutral and hit the emergency flashers and start pulling over while madly pumping the accelerator pedal. It doesn't stall completely, and but it stutters like crazy. This may last 5 or 15 seconds, then the engine corrects and resumes. I've seen the MAF sensor reading at 0 while going 50 MPH. The freeze frame showed the engine load at 0 at the exact same instant.

At it's worst:Sometimes it won't start, or will seem to start for a second then stall. If it does start, You fight it while pumping the gas pedal. After many attempts, it finally smooths out like nothing was ever wrong and it runs like a champ.

At idle, sometimes it can completely stall. But you always get a stutter that warns you it's about to stall. So you kick the accelerator, unless you're my wife who lets it stall while she's freaking out in the middle of the 6 lane intersection.

At other times you can put the car in neutral or park and try try try to get it to hold a steady RPM around 2500. Instead of a nice steady sound you hear the engine rev up, go down, rev up, go down etc. Vroom, vroom, vroom when it's supposed to be steady even revv sound. If you're not lucky you have to pump the accelerator pedal like crazy to keep her from stalling. Then after a while she forgives you and acts like nothing was ever wrong (there's a joke in there somewhere). Unless you're my wife and you keep it in drive, and the car surges and slows and surges slows and you get scared and slam on the brakes and it stalls. I got one code from one "leave it in drive while it surges and slows" event relating to gear ratio. I don't remember the code.

You can drive the car 50 miles and never have a problem or you may not be able to get it out of your driveway, or maybe you'll stall at the worst possible place and moment.

Before I cleaned the MAF sensor, the problem was more severe and happened about every other trip. After I cleaned the MAF sensor, the problem is even more intermittent (if you can call that better). I had one severe episode since I cleaned the MAF, and I was going about 25 MPH and had to pull over and pump the pedal to keep her from stalling. I wish I had my code meter with me but I didn't. After about 3 minutes she revved smoothly for me again we drove away like nothing was ever wrong. I've spent hours trying to get it to do that again with the ODBII meter attached but no joy so far.

Trying to make it happen:The only way so far is to get the car up to 45 mph, then stomp the accelerator pedal to the floor board. As the RPM's just about red line, it'll start stuttering surging stalling like I described above. But it doesn't last but 5 to 10 seconds or so.

Speculation:I'm stumped. Could the EGR valve be doing this? Could the MAF sensor really be "occasionally" bad? I'd hate to spend $220 for a reconditioned one just to find out if it didn't fix the problem.

This has stumped 3 experienced mechanics with varying levels of expertise from pro to intermediate. No I haven't taken it to the dealer and I really, r e a l l y don't want to.

Right now I'm heading toward MAF replacement, or dreading pulling the EGR Valve to clean / test it. I also want to check the fuel pressure with my old AC gague, but I haven't figured out how to make "Tea with fittings yet" . If anybody has already been there and done that please post how you did it.

Any suggestions?

[elwesso]

WElcome to NICO!

Very impressive analysis, its so nice to be able to have all of this to go by! Very good job!

Normally when the MAF fails it fails like you stated, intermittently. I would replace the MAF... You can get a used one from a 96 Nissan 300ZX (sometimes caled the N62 MAF). I would get a known good used one over a reconditioned one, because for all you know it could be they took a bad one and sprayed cleaner on it and called it good!

The EGR is a seperate issue. Your EGR passages are probably clogged and they will need to be cleaned. Theres plenty of posts in the J30 forum how to cleanthe EGR passages on the J.

I will say that 90% chance the MAF will fix the issue... Unless of course its a connector issues, but the 96+ used a different style connector that isnt prone to failure. Check the connector and make sure it clean, assuming you havent already done that.

[wirelessnut]

Thank you Elwesso.

I finally found a used MAF for just under $100 and installed it a couple of weeks ago, and it purrs like a kitten again. I'm only getting the EGR Flow error now, but that wasn't causing the serious driving issues we were having.

This forum is awesome.

Thanks again.

[maxnix]

Stick to OEM air and fuel filters and BG44K for cleaing the injectors passively. Use only proper OEM NGK plugs.

Well documentd post.
Modified by maxnix at 6:15 AM 8/6/2007

[supadave]

hmmm glad i found this forum cuz my j30 was doing the same thing and now its at its harshest today ever since i pulled in the parking lot at work and it stalled out as soon as i parked, i tried to start it and i couldnt get it to start..... after work it started right up, but the exhaust smelled really bad. i know that my egr sensor is out ( from a previous trip to autozone code reading) but i dont know if that would cause stalling or not im not sure about the MAF, where is it located. and is there ne repair books for a j30, as i havent found ne.

[maxnix]

and is there ne repair books for a j30, as i havent found ne.

FSM at http://www.phatg20.net (you'll need WinRAR) or with TSB at http://www.nissan-techinfo.com/infiniti/ for a one day subscription.

Welcome to NICO!

[supadave]

awesome maxnix preciate it. i guess im gonna try cleaning the MAF hopefully that works if it doesnt im stuck.

[maxnix]

i would be more concerned with the MAF connector or the conditon of the intake path.

Plugs? Fuel filter? Recent maintenance history?

[supadave]

good point i took it to autozone for another code read, oxygen sensor 2 in bank 1 is bad, engine temperature sensor, knock sensor. while i was there i took a look at the air filter wow that needed to be change tons of sh** in it and i bought some coolant, after i put the new filter in i noticed a drastic change in the engine its running a whole lot better but it still acts a like it wants to stall out every once in a while i dont know if fixing the oxygen sensor would fix the prob. i need to change the spark plugs, possibly fuel filter, how would i go about getting the maintenance history. i bought the car at a lil tote the note lot. hopefully this fix will last me till payday, lol

[maxnix]

how would i go about getting the maintenance history.

If you don't know a friendly Infiniti service writer who will pull it for you as a print out, register your self as the car's new owner at Infiniti Customer Service. They will read you a service history, but will not send you one. Might take a couple of days to get it out of archive.

New owners with no service history replace all fluids, plugs, filters and worn suspension items (rubber especially) to start at a known baseline.

[supadave]

damn thats pretty awesome ill have to check into that do you know if all infiniti dealerships do that or would i just have to call around

[supadave]

hey max where would the knock sensor be located i looked on the repair man. u sent me to and it didnt really show where it was

[elwesso]

You can see it in the EM section, OUTER COMPONENTS PARTS.

[supadave]

hey guys quick update replaced the 20 dollar coolant sensor and its running fine check engine light is off now so preciate the tips and advice

Thanks