I've been trying to use the search in hopes that someone else has had similar issues to mine, but I haven't found anything that sounded close to what I'm experiencing, but I could have very well overlooked it. So if this is any kind of repeat questions, I apologize.

Like the title says, I'm having an odd idle problem. When driving normally and not putting too much on the "GO" pedal, my idle is fine ( or seems to be: 850ish in Park, 650ish in Drive ). But if I get too heavy on the pedal, my idle will jump up to 900ish in drive and 1.5k or higher in Park. But if I put it in Park, turn it off, and turn it back on, the idle will return to normal. Could this be an IAC problem?

As for the warm start up, whenever I try to start the truck while its warm, as I crank it, the truck will kind of sputter in the lower RPMs for a second, jumps to about 1.1k or 1.2k RPMs, and then returns to normal. I'm wondering if there is a possibility somehow the two are related, or if they are seperate issues.


Any ideas would be greatly appreciated.

 

Does anyone have an idea..?

 

I have just had the same issue with my 2001 excursion v-10. I read through all the ideas here and started working on it. I first looked for any vacuum leaks. I did not see any, but put in a new pcv valve from napa. The hose end was larger than my original, and I didn't notice until I got it installed, I sure wasn't paying attention. I was able to go directly from that and to the pcv inlet on the passenger side of the throttle body with a aftermarket hose. I also replaced the IAC motor on the back of the throttle body because i thought that it might be the problem. I did clean the throttle body and also cleaned the Mass air flow sensor with the cleaner that was designed to do that. Reassembled everything it seemed to run well. Before it would idle at up to 3000 rpm after it was at normal temperature. My work seemed to fix that isssue, although it seemed to idle down slower than normal after releasing the accelerator. Later i had it quit right after starting when shifting into drive. It did that like 8 times. Now my wife took it to a great mechanic that I have known for years and he first cleans out the throttle body where the butterfly throttle valve is and checks everything. It is still there, but he said he has let it idle and ran it and he says that there is no more problems. He says that if the throttle valve sticks open slightly, then it causes issues like that too because the throttle position sensor is showing that it should be above idle, but is getting conflicting reports from the MAF sensor and the IAC motor. The computer gets confused. He says it is now fixed and I will see for myself in a couple of days. You can e-mail me at justinvdk1979@live.com if you have any more questions.