rough idle at complete stop

[bobxrion]

so i just got this '92 explorer and im liking it alot, but yesterday it started idling really roughly. this only happens when i stop... the rpms will go down to close to 500 but it hasnt stalled as of yet. i put in some fuel treatment stuff incase it was water or something. idk im gonna fill the tank soon and then see wat happens... if you have any ideas please do say. thank you guys!

 

[Dewdnoc]

I just got my 96 a week ago. Having the same trouble as well. If i start the car and let it idol for about a minute, it starts to sputter out. Figure I'd take this weekend to change out all of the fluids, hopefully that helps.

 

[Roadrunner777]

Easy cheap first steps are to clean your Mass Airflow sensor, and Idle Air Control Valve. Both are on top of the engine, easy to get to and remove, and cleaning is well documented on this forum. Check the plastic air duct across the front for cracks... it needs to be air-tight.

Also, at some point, disconnect neg battery terminal for 30 minutes and reconnect, run engine for 20 minutes of typical driving for computer to relearn engine.

Any check engine lights?

This engine idles rather low, and consequently, a little rough on the best of days. Search on rough idle and get ready to do some reading.

 

[Jason94sport]

Could be a bad or out of spec TPS sensor too.

 

[bobxrion]

thanks for the tips RR i actually read all over this forum before i posted this and found most were also having other problems. i will go find the cleaning guide and see if that helps. thanks alot.
p.s. no check engine light

 

[bobxrion]

ok so it got better after i put more gas in it.... i think it might have been that i put too much ethanol in it. the gas i had in it was 89 oct that had more than normal amount of ethanol. i didnt have the time today to check and clean the maf or iac. idk bout tomorow either. i think monday ill have lots of time... busy weekend...

 

[Roadrunner777]

The MAF has uses a T-20 security bit with a pin and hole. You may want to look at that and get the right tool bit if you don't have one. A good hardware store will have them (Ace Hardware does in my area). Use electronic grade cleaning spray, or better yet, MAF cleaning spray, available at Orielly's.

 

[bobxrion]

thanks alot for the tips. yesterday i was able to clean the IAC and undo the battery for 30 mins. its idling better so im quite happy. soon i hope to have time to check my MAF... we shall see thanks again

 

[bobxrion]

so now my idle is higher than normal around 1100 or so. i been looking around the forums and found a ton of info thanks alot guys. so i found vacuum leaks could cause this idle. fyi when it went to low idle it was rough still. so i found the tree had a vac leak, it was meant to go to the air box. so i plugged it and its idling better. thanks alot for all the tips guys!

 

[Roadrunner777]

I guess I'm not sure if you are saying your idle is now normal or high. When you think you have fixed everything you can find, you will need to disconnect the battery for 30 minutes, reconnect and drive normally for 15 minutes or so. This will cause the computer to relearn the correct idle. If you are at a normal idle now, congratulations! We only have hints and stories. You are the one turning wrenches and fixing your truck, good work!

 

[bobxrion]

its idleing a little high right now but its about 800-900 avg. i have not completely plugged the vac leaks yet. hopefully that will be tommorow. i will do the batt thing then if it seems to idle good.

 

[bobxrion]

Thanks to everyones help and this site I have learned its probably my thermastat causing the high idle I haven't had the time to fix it but its running pretty good none the less thx guys!