Very High Idle Only After Warmed Up About 20 Mins.????

[BKM48198]

My sons car starts and runs good for about 20 mins and then the Idle goes up between 2-3000 rpm, what could cause this? Checked the codes and he got , 81, 82, 85, 84 & 95, With 34 in memory.......the car has had all the emissions stuff removed and he is changing the EGR out now with another one he has, he swapped out the fuel pressure regulator last night and it still does the same thing, runs fine for about 20 mins and then the idle goes up too much to drive it. He has done a base idle reset also.

 

[TOOLOW91]

One of those codes for an ECT sensor ? If it drops out or has an issue it will read like -33 deg and keep the car constantly trying to warm up . Hence the high idle .


Sent from my iPhone using my fingers while my auto correct makes me seem illiterate

 

[jrichker]

You guys with idle/stall problems could save a lot of time chasing your tails if you would go through the Surging Idle Checklist. Over 50 different people contributed information to it. The first two posts have all the fixes, and steps through the how to find and fix your idle problems without spending a lot of time and money. It includes how to dump the computer codes quickly and simply as one of the first steps. I continue to update it as more people post fixes or ask questions. You can post questions to that sticky and have your name and idle problem recognized. The guys with original problems and fixes get their posts added to the main fix.

It's free, I don't get anything for the use of it except knowing I helped a fellow Mustang enthusiast with his car. At last check, it had more than 200,000 hits, which indicates it does help fix idle problems quickly and inexpensively.

 

[BKM48198]

One of those codes for an ECT sensor ? If it drops out or has an issue it will read like -33 deg and keep the car constantly trying to warm up . Hence the high idle .


Sent from my iPhone using my fingers while my auto correct makes me seem illiterate

The codes seem to be emissions codes and EGR code, emissions stuff was all removed long ago and the car had been running good but after sitting all winter it started acting up. I've been working 12 hour days and haven't had a chance to go look at it myself but will this weekend if cleaning out the EGR didn't help, he took the EGR off and was going to clean it out to try to get rid of built up carbon. It just seems odd that it runs good for about 20 mins and then the idle goes way up, he has tried a base idle reset, cleaned the MAF wires, set the TPS, cleaned the IAC and TB.

 

[jrichker]

The codes seem to be emissions codes and EGR code, emissions stuff was all removed long ago and the car had been running good but after sitting all winter it started acting up. I've been working 12 hour days and haven't had a chance to go look at it myself but will this weekend if cleaning out the EGR didn't help, he took the EGR off and was going to clean it out to try to get rid of built up carbon. It just seems odd that it runs good for about 20 mins and then the idle goes way up, he has tried a base idle reset, cleaned the MAF wires, set the TPS, cleaned the IAC and TB.

Do the Surging Idle Checklist one step at a time, the answer is in there...

 

[TOOLOW91]

The codes seem to be emissions codes and EGR code, emissions stuff was all removed long ago and the car had been running good but after sitting all winter it started acting up. I've been working 12 hour days and haven't had a chance to go look at it myself but will this weekend if cleaning out the EGR didn't help, he took the EGR off and was going to clean it out to try to get rid of built up carbon. It just seems odd that it runs good for about 20 mins and then the idle goes way up, he has tried a base idle reset, cleaned the MAF wires, set the TPS, cleaned the IAC and TB.

Like I said . Check the ECT sensor as well as the idle check list . If the sensor reads cold the idle sticks trying to warm the car up . I've had this issue and chased my tail

 

[BKM48198]

Like I said . Check the ECT sensor as well as the idle check list . If the sensor reads cold the idle sticks trying to warm the car up . I've had this issue and chased my tail

........OK Thanks....I thought you were asking if the code was for the ECT----"One of those codes for an ECT sensor ?"....I'll have him check that out.

 

[TOOLOW91]

........OK Thanks....I thought you were asking if the code was for the ECT----"One of those codes for an ECT sensor ?"....I'll have him check that out.

I did ask that as well because you listed a host of codes .