car is surging at idle

[slingshot37091]

well,when it idles at times it idles real low(about 1000 rpm)but the problem is it surges at times.it'll idle up and down in park and in gear.i checked alternator.the car runs out great though,all power on road just surges and sometimes misses at idle and was dieing out at idle,can't figure it out.is it in the charging system or throttle body or what?

[vicv]

Check the IAC for proper operation. You don't state what year but the IAC is a common issue with idle problems. If CEL is on get the codes and post them. Could be a vac leak but the light should be on.

[nspbravada]

Originally Posted by slingshot37091

well,when it idles at times it idles real low(about 1000 rpm)but the problem is it surges at times.it'll idle up and down in park and in gear.i checked alternator.the car runs out great though,all power on road just surges and sometimes misses at idle and was dieing out at idle,can't figure it out.is it in the charging system or throttle body or what?

I have experienced the same problem in a 2003 with a 4.6 liter motor. It has happened to me twice and my wife a couple of times too. I never did determine the root cause and it hasn't happend over the past year. The one common denominator was that the truck was cold. My theory was that the computer was transitioning from a cold start mode to a normal temp mode but I'm no expert.

[srercrcr]

The throttle plate needs to be cleaned twice a year (both sides) ....maintenance.

[jaguar02]

My 94 limited does the same thing. I cleaned the throttle plate inside and out, removed the IAC and cleaned it but still have the idle that surges but did improve a little. Check engine light still comes on though after about 15 min of driving. Will the EGR valve cause this issue iff it is bad?