2001 pathfinder w\VQ35DE stalling

[dostrander]

Hi guys,
I have a 2001 Pathfinder with a VQ35DE that is stalling at stop lights\signs intermittently, after a couple seconds it'll drop down to about 500 RPM then after a couple more seconds it stalls but will start back up. It has not lit up the CEL and I just had it smogged the other day and the guy code scanned it for me and nothing showed up. The air cleaner is only a couple of months old, the spark plugs are about 4 months. I've cleaned the throttle body and the air gap around the throttle valve plate, and I can't find any vacuum leaks. I Seafoamed it (the half thru the intake/half thru the gas tank method) about 3 weeks ago and it started up about a week after that. Any ideas guy's?

TIA
Daniel

[atraudes]

Did this start happening suddenly, or over time?

How old is the fuel filter? They get surprisingly dirty which can restrict flow.

[dostrander]

Pretty suddenly, and the fuel filter is about 14-15 months old. It started up about two weeks ago, about a week after Seafoaming.

[Buzzman]

Sounds like another pending IACV failure. Your Pathfinder is the right vintage for this to happen.
If that is the case, replace the IACV before it blows your ECM.
Seems like every second thread lately is about this problem.
Check the other threads related to this stalling problem and you'll see what I mean.

[atraudes]

Don't the failing IACVs throw codes though? Or not always?

[dostrander]

Is there a test procedure can do before just replacing it? It's under the plenum right?

[4xq]

I might take a wild a$$ed guess and say you seafoamed thru the air cleaner, which probably got seafoam on your maf? If so, I would try cleaning it with some maf cleaner.

Atraudes, you've been busy posting the last few weeks. Nice job helping out!

[dostrander]

Sorry 4xq that's a negative, I used the brake booster inlet.

[atraudes]

Atraudes, you've been busy posting the last few weeks. Nice job helping out!

I've been learning a bunch

[dostrander]

Could an issue with the evap canister purge volume control solenoid valve cause symptoms like this (stalling at stop lights\signs intermittently, after a couple seconds it'll drop down to about 500 RPM then after a couple more seconds it stalls but will start back up). When I was going to do the Seafoam, I was thinking about using the vacuum inlet for the valve because the ports located right behind and on center with the throttle body (thought would get more even distribution across the cylinders there instead of the suggested brake booster port. I had the line disconnected for a few seconds before deciding to go with the recommended brake booster (chickened out is more like it!).

[4xq]

I would not expect that - that system gets checked pretty closely, and that valve should throw a code if there is a problem.

This seems to be happening when you are warmed up, correct? Here are some things to look at:

1. Pull on the gas pedal at idle and see if that causes the idle to drop. You are looking for some hangup in the throttle cable. Also manually operate the throttle assembly and see if you feel any hangups.

Press the gas pedal, then let the throttle body return to the idle position by itself. Then use your hand to try and close the throttle plate further while you watch the throttle
plate for movement. Again, you are checking for a hangup.

2. Clean the maf if that hasn't been done recently.

3. Adjust the throttle position sensor. Procedure is in the service manual. Make sure voltages are looking good.

4. Do the idle relearn procedure after you have checked the items above.

5. Look at the booster hose you used to seafoam the engine. Make sure it is tight, and no cracks. If all else fails, try a new brake booster check valve. They are pretty cheap. See if you can associate idle problems with stepping on the brake pedal.

Can't say those will solve the problem. Just throwing out ideas!

[dostrander]

Thanks for the point list 4xq, will run through them and post results. Correct about after warm-up, usually after driving around after an hour or so. Looked through the service manual, couldn't find a reference to "idle relearn procedure" is it the "idle air volume learning"?

[4xq]

Yep. Sorry, didn't look it up.