PDA

View Full Version : 1992 Chevy idle problem


Gatewayuser
11-28-2004, 11:28 PM
My 92 Chevy 1500 2wd auto with a 4.3 not a vortec won't idle right. The truck idles fine for about 5mins until it gets warmed up. We have tried everything to fix it but nothing helps, GM does'nt even know whats wrong. Has any body heard of this, and what can you do to fix it?

Eric 1
11-29-2004, 07:36 PM
Does it run good and just not idle or after it warms up will it not run at all.

Gatewayuser
11-29-2004, 07:44 PM
after warm up it will run at 250-550 RPMs sometimes stall

Eric 1
11-29-2004, 07:51 PM
after warm up it will run at 250-550 RPMs sometimes stall

Ok, but if you rev it alittle will it smooth out some? or will it stutter and run rough. Could you drive it as long as it did not have to stop. There is a reason i am asking this.

Gatewayuser
11-29-2004, 08:03 PM
It drives fine but what I forgot to say is that it does that when in drive. If I put it in N then it will run some what ok.

grass_cuttin_fool
11-29-2004, 08:08 PM
Im taking a shot in the dark here, does the shifter linkage have anything to do with the throttle position sensor or MAP sensor, just wonder if that could be it since it seems to be better in netrual???????/

Eric 1
11-29-2004, 08:11 PM
It drives fine but what I forgot to say is that it does that when in drive. If I put it in N then it will run some what ok.

Ok, seems like your Idle air control valve is not working right. When you put it in D it bogs down the engine some from the trans trying to pull. It sound's like the computer is not getting the signal or a sensor is not telling the engine to idle up some. Thus the reason the IAC is my first guess.

Or it could be the egr is plugged, that is a common problem on the older 4.3's. But if that were the case it would run just alittle rough.

If the "check engine" light is on, take it to an Auto Zone and have them get the codes off the ecm and that will tell you if it is the sensors, it will also pinpoint the bad one (most of the time)lol.

Eric 1
11-29-2004, 08:12 PM
Im taking a shot in the dark here, does the shifter linkage have anything to do with the throttle position sensor or MAP sensor, just wonder if that could be it since it seems to be better in netrual???????/

No...............

Gatewayuser
11-29-2004, 08:12 PM
Could be I will have to see if thats it. How do you think I could fix that if it is?

Eric 1
11-29-2004, 08:17 PM
Could be I will have to see if thats it. How do you think I could fix that if it is?

Sometimes you can adjust them some, but that is vary hard to explain. You most likely will have to replace any sensor that is bad.

Just to see, I just called my local Auto Zone. The IAC is $27.99, in stock.Not to bad.

Gatewayuser
11-29-2004, 08:18 PM
Thank you very much its worth a try!

Eric 1
11-29-2004, 08:23 PM
I am kinda surprised its that cheap myself. But i hate to just through parts at it. But that's about all i can tell you without hearing it run.

Is the check engine light on?

Let me know if it helps any.

Gatewayuser
11-29-2004, 08:26 PM
Well just talked to my dad and he said he replaced that already and the reverse neutral sensor, but he said the IAC might need adjusted like you said. My Dad said that might fix it and thanks.

Gatewayuser
11-29-2004, 08:28 PM
Check engine light is not on.

Eric 1
11-29-2004, 08:31 PM
Your welcome.


I think it would need to be adjusted out, but i am not sure on that.

Good luck, let me know what fixes it, I am curios now.

Gatewayuser
11-29-2004, 08:33 PM
Ok i will thanks

Eric 1
11-29-2004, 08:42 PM
One more thing.

Check the vacuum hose that goes from the front of the throttle body over to the PCV valve. Check to see if it is plugged on either end, or close to plugged. commonly on the end closer to the TB. If it is pluged the engine is not getting any vacuum at idle, then when you open it up some it gets enough vacuum through the throttle plates.If it is plugged go ahead and replace the PCV valve, it will be about $4.

To clean it out just poke it with a small screwdriver till you get the plug busted up then spray some carb cleaner through it.

Gatewayuser
11-29-2004, 08:48 PM
I know i changed the pcv valve but i can't remember if i changed the vacuum hose i'll have to check that too.

jc1
11-30-2004, 09:53 PM
Sometimes the distributor magnet gets a crack in it and when you put it inot gear the signal will become erractic which then affects the timing of the spark from th coil to the distributor. If you locate the timing connector for the distributor that is on the firewall on the passenger side sometomes behind a plastic cover, You can unplug that connector it is a tan and black wire, if it then runs better that is a sign that the magnet is cracked.

Gatewayuser
11-30-2004, 11:09 PM
I'll try that, thanks

Eric 1
12-02-2004, 01:33 PM
Any luck yet?

Gatewayuser
12-02-2004, 10:05 PM
I have been sick with a cold and its been raining outside, but I'm feeling better now so I will try to fix it tomorrow.

Gatewayuser
07-25-2005, 10:30 AM
ITS FIXED!!! I put a 160 cold thermostat and a cold clutch fan in and was shocked when that fixed it. I'm going to put a chip, MSD system with wires,and k&n intake in next week. Thanks for all the help though!