Engine Idle and Stalling Problem

[ALC1717]

I am experiencing an Intermittant Idle and Stalling Problem on my 2001 Stock engine VX. I already changed the Air Flow Sensor which worked for a while then Yesterday it started stalling again. I was told if it was the Intake Manifold Gasket it would happen all the time? I am not getting a Check Engine Light! Also the gas Mileage has gone down considerably!

[Jonnie]

It was the Throttle Position Sensor when this happened to me.

[jeeperkate]

I am right in the midst of this same problem. I changed the IAC and the TPS. It seems to be doing better, but I haven't had enough time to test it out. I know another member said he had to change the Fuel Pressure Regulator. You may want to try the TPS and then the Fuel Pressure Regulator.

ALSO - I have no Check Engine Light either.

[89Vette]

Go to Autozone. Rent (for free) their fuel pressure tester. Easy to use.

Measure FP. Spray propane, or ether around base of manifold.

If pressure isn't 34-39 (steady) and if idle is affected by the manifold test, you've found the source of the problem.

Negative on the above two, and it may be the TPS. A simple volt/ohm meter will show if TPS sensors aren't consistent.

[Gussie2000]

Hey albert i told you yesterday your idling and stalling issues can be the TPS ( Throttle position sensor ) or intake manifold gasket which is a very common issue with these engines and seeems i am not the only one who is saying the same...

[Paul_A]

Manifold gaskets for sure.... :(
It only takes an hour or two to lift the manifold. Personally. I'd start there and not go possibly wasting cash on sensors and the like. It's a VERY common problem. when you replace them don't torque the bolts down to the recommended figure... that'll crack the new gaskets for sure. 13 ft lbs is about right.

[SilverBullet75]

I had same symptoms a while back.
Mine was the Idle Air Solenoid.
You can remove it and clean the inside with brake cleaner and a small wire brush.

http://www.vehicross.info/gallery/data/500/engine.jpg

[ALC1717]

Thank you, We diagnosed that this was the problem and I ordered a new one from Merlin at Isuzu for $67 so I hope that was it !

[Vendetta]

Glad to hear another one solved. Seems to be going around a lot lately: http://www.vehicross.info/forums/showthread.php?t=21858&page=3#post248880

[jeeperkate]

Thank you, We diagnosed that this was the problem and I ordered a new one from Merlin at Isuzu for $67 so I hope that was it !

I got mine from Autozone - $45...Duralast AC143

Just an FYI :smilegray

[Bulldoggie]

I had same symptoms a while back.
Mine was the Idle Air Solenoid.
You can remove it and clean the inside with brake cleaner and a small wire brush.

http://www.vehicross.info/gallery/data/500/engine.jpg

I found the large hose clamp has loosened on mine more than once.
The big one on the intake tube in the lower corner of the red box outlined in this picture.
I've replaced my Fuel regulator, TPS, and cleaned the IAC solenoid, all the cheaper stuff, but my problem still plagues me. One of these should cause a problem every time and not just once in a while?
I'm thinking of having a smoke test, to look for a Vacuum leak, AND buying a "test" or used MAF. I have finally had some codes other than low flow EGR.
I've had lean fuel on both banks. It's probably the MAF, but at $450. I might have to wait for a Tax return

[ALC1717]

Just a Guess, if your problem is NOT intermittant, it might be the Intake Manifold Gasket. You can spray carb cleaner at the base of both sides of the Intake Manifold. If your Gasket is Bad, the Idle will change and flunctuate !

[yesitdoeshaveteeth]

As crazy as this sounds, I had a very similar problem with intermittent idle and after replacing the IACV and TPS and after having ordered the intake gaskets, I decided to give one last shot at trying to find the obvious before I tore into my intake.......which lead me to find that the culprit was actually the vacuum hose that comes off the Fuel Pressure Regulator. That little $.25 hose was the reason my VX would idle all over the place. When I discovered it, it was chaffed and cracked at both ends, all I did was lop off about a 1/4 inch off both sides and reconnected it to the FPR and the upper intake plenum, its been running fine ever since - Hope that helps!

[ALC1717]

Thanks for Everyone that tried to help with the problem. It was the Idle Air Control Valve. Problem FIXED !

[Bulldoggie]

As crazy as this sounds, I had a very similar problem with intermittent idle and after replacing the IACV and TPS and after having ordered the intake gaskets, I decided to give one last shot at trying to find the obvious before I tore into my intake.......which lead me to find that the culprit was actually the vacuum hose that comes off the Fuel Pressure Regulator. That little $.25 hose was the reason my VX would idle all over the place. When I discovered it, it was chaffed and cracked at both ends, all I did was lop off about a 1/4 inch off both sides and reconnected it to the FPR and the upper intake plenum, its been running fine ever since - Hope that helps!
I didn't like the look of the vacuum hose attached to the fuel pressure regulator, when I changed it (the FPR) That's why I thought Vacuum leaks might be to blame. I would have cut some off the end but there didn't seem enough to stretch. I had a Mechanic friend tell me about a Smoke test, for checking for vacuum leaks. I think I'll pass on the test and start replacing hoses.
I'm glad that you did get good results. That will be my next step for sure!
Can't wait for the rain to stop so I can "Get'r done" :yeso:

[Bulldoggie]

I was in Autozone and I asked for pricing on the MAF and IAC.
He said $100. for the MAF and $50. for the IAC?????
Last time I priced the MAF I was told $475.??????? WTF!
Anyway I pulled the trigger and 10min. later my VX runs like new :bgwo:
AWESOME!
:dan_ban:
I'm not sure which one, but I don't care!
I'm so happy that it's using all 3.5L again...
(I'm guessing it was the MAF all along)

:jump::jump::jump::jump:

[Ldub]

AWESOME!
:dan_ban:
I'm not sure which one, but I don't care!
I'm so happy that it's using all 3.5L again...
(I'm guessing it was the MAF all along)

:jump::jump::jump::jump:

:_wrench:...:dance:...:thumbup: