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Hey, guys. Sorry in advance for what’s probably going to be a ridiculously long post, but this is a car that I’ve been dealing with for a while now and I want to make sure I provide as much information about what’s been done as possible.
The car in question is a 1996 Nissan Maxima GLE automatic. It’s not my car, but it’s been passed around my family since new. For the last decade, it’s been in the “loving” care of a relative who has abused and neglected it so badly that I’m shocked that it runs at all. The car is, quite frankly, a huge pile of garbage, but since she refuses to get rid of it, I’ve been trying to help her at least keep it drivable and somewhat safe.
The Problem: Intermittent stalling at idle that’s extremely inconsistent. I’ve taken the car out for twenty minute test drives and been unable to get it to stall at all. I’ve also had the car stall immediately after starting it, and then continue to stall three or four more times before finally holding its idle and running fine. The car always starts up immediately, and there’s no hard/slow cranking regardless of whether or not it’s stalling. There’s very little warning before the car stalls.
One thing to point out is that the car was running much, much worse when I got my hands on it. It was hesitating and bucking on acceleration, could barely get above 25mph, and would stall anytime it idled for more than a few seconds. I shotgunned a bunch of basic maintenance stuff (listed below) and most of the more serious drivability issues vanished.
Additional Symptoms/Issues: Idle is slightly rough (feels a bit like an intermittent misfire, but no codes). There’s a noticeable loss of power that comes and goes, and seems to be more pronounced shortly before the car stalls. There was also a slight smell of burnt rubber through the vents once while climbing a steep hill, but I’ve never been able to reproduce that. I do know that a belt (99% sure it’s the ac/alternator belt) is slipping.
Recent Work/More Information:
- Valve cover gaskets replaced
- Spark plugs, PCV valve/grommet, air filter, fuel filter replaced (the original 19 year old fuel filter seemed to be the cause of the bucking/hesitation)
- Replaced MAF sensor gasket, air intake boot, several cracked CCV breather hoses, and a bunch of vacuum hoses
- Throttle body and idle air control valve gaskets were both torn, so I replaced those. Cleaned the TB, IACV, and MAF for the hell of it.
- Replaced Camshaft Position Sensor to clear code P0340
- Fixed a bunch of broken wires going to the EVAP canister purge volume control valve to clear code P1445
- Tested the IACV according to the factory service manual (checked for power, resistance test, and removed the valve and made sure it moved freely while switching ignition to “on”). Seems fine.
- Did a basic test of the battery and alternator with a mutlimeter. Battery is 12.4-12.6v with the car off. With the car on, alternator voltage is in the 14.4v range with no load. With everything on it drops to 13.2v, dipping to 12.6-12.8v once the belt starts audibly slipping. Aside from the fact that all of those numbers seem fine, I’m assuming this isn’t the problem since the car isn’t any more likely to stall with a ton of load on the alternator.
[li]It’s leaking oil. Like, a lot. I haven’t been able to pin down where it’s coming from, but to the best of my knowledge the car has never been run while low on oil. - Tested the MAF by watching values with an OBDII scanner and by probing the actual lines with a multimeter. As far as I can tell, it seems fine.
- Used a friend’s smoke tester, but we couldn’t find any leaks after I replaced the valve cover gaskets and a pile of hoses.
- No check engine light, but there’s a stored P0325 (knock sensor) code. I have the new sensor, but I haven’t bothered replacing it yet since it’s a huge PITA and as far as I know, the knock sensor isn’t going to cause the car to stall. No other stored codes after replacing the CPS and fixing the wires to the EVAP canister.
[li]Not sure what normal idle behavior for these cars is, but when starting it generally idles at around 1500rpm in park. It evens out to about 900-1000rpm in park and 700-800rpm in drive.
I think that’s just about everything. I’ve been going at this car just about every weekend, and I’m ready to tear my hair out over this. Everything I do seems to either reduce the frequency of the stalling or make the car run better, but nothing has outright solved the problem. Any and all advice on where to go from here would be greatly appreciated.
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How many miles are on the engine?
Have you tested the MAF? I read that you cleaned it.
There aren’t a lot of things that can cause this issue, but not throw a code.
Does your scan tool do live data? If so, have you compared the O2 outputs with the fuel trims?
Intermittent issues like this will take a few years off your life.
You’re lucky it’s OBD2. My girlfriend’s 1987 Camaro was having issues like this. I replaced damn near every part under the hood and still had the problem. I put it in storage a few years ago and I will probably just swap the motor out at some point. I am in no way indicating this will be your future, I’m just kinda rambling.Whoops, I knew I’d forget something: about 141k miles on the car, so relatively young for its age. Engine and transmission are original.
My scan tool does do live data, and I’ve got a bluetooth scan tool to pair with my tablet for logging as well. I’ve tested the MAF and it seems fine – smooth response to throttle, no weird fluctuations at idle or while driving around. Short term fuel trim seems to follow O2 voltages normally. Fuel trim on both banks is actually pretty normal (~+/- 5% LTFT).
I’m stumped. The only obvious issues right now are an idle that’s slightly rough and a little bit inconsistent in drive. The car isn’t idle hunting, but I have noticed that it doesn’t generally fall back to the same idle after coming to a stop or switching between park and drive. The idle varies between 600-800rpm, becoming noticeably rougher when it decides to idle at the lower end of that range.
Hey George, I don’t suppose you ever solved this issue? I’m going through similar and was about to go down the same road. Upon inspection, was your breather and MAF clean and your intake dirty? I don’t know if dirty air is getting by my filter or if the emissions system dirtied the intake from recirculation being downstream.
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