The Nissan Club banner

1 - 17 of 17 Posts

·
Registered
Joined
·
11 Posts
Discussion Starter #1
My wife's Altima (98, A/T) has been having some intermittent idle issues and some stumbling at part throttle.

It happens about 50% of the time, when coasting or at part throttle it'll stumble. Then when the car is at a stop it won't hold idle. I've already replaced the spark plugs and checked the idle speed, seems to be ok. My next step is to start testing all the emissions and idle control stuff but I'm hoping someone can point me in the right direction first. I haven't checked the timing yet either, will do that as soon as I get ahold of a timing light.

From searching posts on here it looks like it's either a vacuum leak or IACV problem. No codes are being thrown.

It seemed to start after idling the car with A/C on for about 25 minutes in a parking lot last week but that may just be coincidence.

Thanks in advance..
 

·
Registered
Joined
·
2,771 Posts
change the cap and rotor if you havent in a while. definately check for a vacuum leak. also check the intake manifold gasket, that is known to blow on our cars, and it will kill your idle.
 

·
Registered
Joined
·
174 Posts
You may want to check all the simple things first, however if all else fails, you may also want to check your distributor, I had pretty much the same symptoms as you, and here is everything I tired before I changed the distributor. If I changed the disty in the first place, I would not have had to check all those things,but at least they are all replaced now.


1. spark plug wires
2. spark plugs (tried 3 diff't brands and types)
3. Cap and rotor (twice)
4. MAF cleaning - cleaned it like 15 times
5. MAF Transistor - I cleaned it out, there was oil in it
6. Check if EGR Valve is not sticking, and none of the tubes are old and worn out

I gave up and took it to the Dealer and they changed the distributor which was throwing a CAM Position Sensor code, which is built into the distributor, and they also changed a MAF Transistor grounding wire

They also changed a an EGR tube.

the total cost was like almost $1000 CDN, bc the damn distributor was about $700 alone. I could have changed it on my own, but I didnt want to risk it on my own.

Hope that helps!
 

·
Registered
Joined
·
1 Posts
mine too...95 a/t

Mine is doing the same thing. Plugs good...wires good...new fuel filter...new cts...voltage at tps in closed throttle position = .4 volts, not the .5-1.0 volts haynes calls for, in open throttle it is 4.8 volts or so, as it should be, reference voltage is correct too. Will .1 volt too low a reading from the tps cause these symptoms? Mine will stumble, spike the idle and then sometimes die. In answer to one of the earlier responses it is a putt, putt sound at the tail pipe. Thanks for the help.
 

·
Registered
Joined
·
19 Posts
im having the same issues on my 93 manual se. when i try to start it will just crank an crank until i step on the gas then it will fire, idle bad wants to die and feel like its surging while driven. my catconverter stinks like rotten eggs and my tail pipe has what sounds like a misfire or lumpy cam. it has a recent tune up as well . i did get a CEL this morning on my way to work. so something is for sure wrong.
 

·
Glowin' Authority
Joined
·
253 Posts
rotten eggs... not good, but on your cat converter... not possible, correct me if im wrong but the rotten eggs is a colant leak inside the engine? the crank and crank deal sounds like a clogged cat converter... REAL BAD clog, if its clogged bad enough you can punch the gas and go no where...
 

·
Registered
Joined
·
11 Posts
Discussion Starter #15
Hey sorry to start this and bail, but I decided to take it to a shop. Bad idea.

They have no idea what's going wrong and are just replacing things they think might fix it. So far they have replaced the crank angle sensor, and now they want to replace the MAF. If the MAF doesn't fix it they want to move up to replacing the ECU.

I just don't think it's either of those. The issue ONLY happens when the throttle is closed. If you're coasting down it'll stumble a little but since it's auto the engine keeps running. If you hit the gas it smooths out and is fine. It's similar with the idle, if you gas it up it doesn't stumble for a little bit and if you put the AC on it raises the idle enough to keep from stalling.

My wife is pissed now because I'm so negative, the mechanic admits he doesn't know what to do and the Nissan dealer says "replace the ECU ($$$$)"

I'm thinking of taking it back and doing a thorough cleaning and testing of the whole emissions system but that is tedious and I'm not too thrilled about doing it.
 

·
The Don.
Joined
·
6,151 Posts
Sounds to me like an IACV (less likely) or fuel injector (highly likely) issue. But a fuel pressure and vacuum reading would rule out a whole bunch of things.

The ECU rarely goes bad. Someone here recently had a chattering fuel injector that was due to a bad ECU. But don't replace it yet until they can tell you exactly why it is bad.
 

·
Registered
Joined
·
11 Posts
Discussion Starter #17
Well it looked like the air flow meter (MAF?) replacement fixed it. Since the mechanic wasn't 100% sure that was the problem I had him get a used one so we wouldn't be out too much money if it didn't work.

So far the car seems to be running fine and actually seems a bit stronger than before. Thanks for everyone's input.
 
1 - 17 of 17 Posts
Top