Engine Loping At Idle

[justwufn]

I have a 96 4.0 engine and I am experiencing an engine loping problem when I stop at redlights. The engine also is somewhat noisy when I start it in the morning.

My CEL is not on and I was wondering if you guys have any suggestions on what could be causing the problem. Also, should I go by Auto Zone and have them check to see if their engine analyzer will pick up a problem even though the CEL is not on.

My initial reaction is that the Idle Air control valve[IAC] is bad., however I do not want to spend a bunch of money if the fault lies else where. How much does a IAC cost?


Thanks, Johnny

 

[CHuntMD]

Do a search for IAC and find a ton-o-info.

Trying cleaning it first. I got mine cheap at www.fordpartsnetwork.com

Chris

 

[Alec]

Is it loping with the RPM changing, or does it just sound a little off? Have you been running rich or had low mileage lately? If you have been running rich I'd suspect your FPR is going bad. You should also try cleaning your MAS.