[nweatherby]

The car I have is a 1999 Mustang 3.8L. Okay I have had this problem since 30000 miles and the car now has about 115000 miles and nobody can fix it so far. I have noticed that when I drive my car sometimes at idle at a stop light it wants to jump 200-500rpms. This is annoying but not my major concern. The major concern comes from shwne I drive it mostly on the freeway then park it for 15-20 Minutes and come back out and start it up the engine almost wants to stall. This is especially bad when reversing. I also get the rpm surge when I am stuck in traffic for a long time say a wreck on the interstate. I am contemplating buying an ELM5 scanner to help me figure it out. Anyway the things I have done so far is replaced plugs, PCV Valve. Cleaned out throttle body and Idle Air Control. Cleaned MAF Wire very carefully.Checked Throttle Position Setting voltage which was 1.0 a little high. Any ideas on what could cause this and whether I should get the scanner. Thanks all

[Cricket]

man this problem is starting to show up more and more with the new edge sixers. Go ahead, and get your computer checked.

[97stanger]

Originally Posted by Cricket man this problem is starting to show up more and more with the new edge sixers. Go ahead, and get your computer checked.

+1 get computer checked. just the other day someone made a post about the same thing,.

[ROUSHME661]

yea it was me that made a post the other day .... except my rpms skyrocketed everytime i put the clutch in ..try reseting ur computer that helped mine ..

[97stanger]

Originally Posted by ROUSHME661 yea it was me that made a post the other day .... except my rpms skyrocketed everytime i put the clutch in ..try reseting ur computer that helped mine ..

yeah, sorry i couldnt remember your name. lol. thanks for the input though! Good Luck with your problem.

[Juggalo_X]

i had a verry erratic idle putting fuel system treatment in and resetting my computer with a hand held scanner seems to have completely solved the issue for me. but it would bounce around like crazy at a stop but it was the worse when it first started it almost would stall some times and when i put the peddle down it would just cough and puke i had the exact same symptoms.