97 f150 4.6 intermittent rough idle when warm
Searched the threads and tried many of the items found there, can't find the problem. 121k miles. Happens only when engine is warmed up, shakes and feels like it will die at some stop lights, runs fine driving no power loss, etc. No shake if it is in park.
Used to have check engine light for egr flow, no light since bypassing broken vacuum canister (see below)
Mechanic replaced: EGR valve
Metal tube from exhaust to egr
Found cracked vacuum cannister in passenger side wheel well, bypassed it
I replaced: spark plugs with bosch 4's (is it a big deal that they aren't motorcraft?)
wires with oem
checked for vacuum leaks as best I could, no smoke machine, didn't find any vacuum leaks
cleaned throttle body
cleaned what I think is the idle control valve (on top and to the back of intake)
don't know if it is related but AC compressor makes a loud metallic click when engaging/disengaging
Is this likely to be an o2 sensor? Is there a way to test the idle control valve? If it was the Idle control valve, would it shake when engine is still cold? Thanks a lot for any help, I am stuck at this point.
Last edited by saaber; 12-06-2007 at 06:11 PM.