hi new here i just redone my 2.8 87 v6 in my s10 .sence start up i have had some problems that you wouldn't believe . my lastest problem and only problem now i have and would love some help with is after the truck warms up under the hood the truck does not want to idle in gear it will sometimes idle up and hold good but then all the sudden idle down and shut off. and if your in gear and at an idle and but the a/c on shuts off right awaythis is only when hot when its cold now problems at all please help!i have changed iac, ecm, plugs wires ect....

 

What did you redo on your engine?

Have you cleaned or replaced the EGR valve? How old is the O2 sensor?

 

i rebuilt it i have not replaced the egr the o 2 sen is new auto zone special i was wondeing could it be int module i have fixed all vacuum leaks so i know its not that.its only after its hot that it does this .

 

MAP sensor new?

Try cleaning the EGR valve.

 

no map is not new took it down and had them test it they said it was ok i'll try the eg cleaning see if that works don't understand why it only happens once the under hood gets hot i'll keep you posted

 

There are two possibilities here.

#1 - the problem is sensor related. The reason for the temperature relation is due to the transition from open loop to closed loop operation. When in open loop operation, the PCM is using pre-defined tables for spark and fuel. Once the PCM has switched to closed loop operation, it uses all of its sensors to dynamically control spark and fuel. If one of the critical sensors is feeding bad data, it can cause problems. To test this, get the truck up to operating temperature and then shut off the engine and restart it. If the problem is still present directly after restarting, then it is not an open/closed loop issue as the engine will always be in closed loop upon initial start up.

#2 - Heat related issue. The most common issues with heat are the coil and/or ICM. Both should be able to be tested at your local auto parts store. Have them test them repeatedly (10+ times) to stress the ICM and coil so both components heat up.

 

ok i'll do that thank you for your help the chevy place had it and said it was just a vacuum leak and wanted 389 dollars to fix it so a friend told me about this site and to check it out i'm sure glad i did i'll be telling all my friends about it i'll keep you posted