hey all.

I've been having this problem for about a year now and now that it's cold it's finally bad. Once i start the truck (cold start only), the idle surges up and down a bit and if I don't let it warm up, it kills when I put it into gear (reverse).

It doesn't kill if i don't put it into gear, and once it's warm there are no issues.

I've done all of the obvious, temp sensor, plugs, caps, IAC etc. No vacume leaks that I can find. I did use teflon tape on the temp sensor..which i believe is not good..do you think that could create this much of a problem. I only have this problem when the weather is below 60 degrees or so. Also the temp sensor is aftermarket.

let me know if anyone has any other ideas.

Teflon tape on the temp sensor is not good, sensor will send erratic readings, not sure if would cause the problems you are having. I would pull the sensor out and clean the threads up real good (sensor and block) and put it back to see if anything changes.

does anyone else have an idea about this cold engine surging idle? No issue when warm. Only at cold start-up after sittng for 6-8 hours.

read the thread " Idle surge" below it might be some help. What model is the truck your working on and what engine?

the idle surge thread it totally different, his was all the time.

the idle surge thread it totally different, his was all the time.

Yes his was all the time; however, you should still check the egr valve and gasket. Perhaps when yours get warm, the leak seals due to heat and expansion.

Does the EGR hold a vacuum when cold? Does the MAP hold a vacuum when cold? Check the hoses carefully. On mine, the MAP vacuum hose would not hold a vacuum and I had a surging idle.

Tape on the sensor should not be an issue since the sensor is a 2 wire sensor. The tape is not needed since they usually come with thread sealant already on the threads.

//2000CAYukon

thanks yukon,

the egr seems to be holding. I'm going to check out the map hoses etc. I read one of your other posts about that. I have a day off monday, im gonna check it out. I let you know what happens.

g