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Rough Idle upcoming Smog Check

J.A.F.E.

Active Member
Joined
November 22, 2007
Messages
65
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City, State
North Hollywood, CA
Year, Model & Trim Level
'00 XLT
I have a 2000 Explorer with a 5.0. The idle is slightly rough especially when cold. Sometimes it evens out when warm but on occasion the roughness remains. No codes and no pending codes. Plugs are stock Autolites with less than 5000 miles the wires were replaced with the plugs. I did the upper intake gasket about the same time as the plugs. The coil packs were replaced about 20 or 30k miles ago. Engine has almost 125k

I recently drove from LA to Reno and back with no issues and I ran a can of Seafoam through the gas tank at that time.

I have an upcoming smog check and need it to pass as this is my DD.

Any ideas?
 






If idling is the only problem, I would start with the IAC (idle air control). Some clean them successfully, but may need to be replaced.

I have a 2000 Explorer with a 5.0. The idle is slightly rough especially when cold. Sometimes it evens out when warm but on occasion the roughness remains. No codes and no pending codes. Plugs are stock Autolites with less than 5000 miles the wires were replaced with the plugs. I did the upper intake gasket about the same time as the plugs. The coil packs were replaced about 20 or 30k miles ago. Engine has almost 125k

I recently drove from LA to Reno and back with no issues and I ran a can of Seafoam through the gas tank at that time.

I have an upcoming smog check and need it to pass as this is my DD.

Any ideas?
 






Thank you 1998Exp. It seems to be mainly at idle it runs strong and doesn't stumble.

I will replace the IAC - I had a hunch it might be involved.
 






Problem solved. I replaced the IAC which smoothed out the idle for the most part but some roughness persisted. In checking around I discovered the Cam sensor has some known issues - including a chrip and I had one I thought was an idler. I replaced cam sensor and an extended drive and now it idles like it should. It passed smog with better numbers than two years ago but I had a ground problem then and I suspect that brought the numbers up.

The bearings on the old sensor unit are really stiff so it was time for the sensor - as far as I know it was the original and now no more chirp.
 






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