I have a 2002 Sable with the Duratec DOHC and 76000 miles. I've had this on-going intermittent rough idle for quite some time and need new ideas on how to solve it. Took it to a mechanic today and he wasn't any help. Here are the details on the problem and attempted fixes to date:
Rough idle (probable mis-fire) at start up and after the car warms up. Most prevalent when A/C is turned on (whether heat or AC). Worse on humid days. Only check engine light has been 1 occurance of "misfire on cylinder 3 during first 1000 revolutions". No other codes.
Here is what has been done so far: New plugs, wires and ignition coil. Replaced IAC and the PCV elbow hose connecting the UIM (clearly the PCV hose was bad. The ignition wires were also bad and arcing. Had the UIM off and checked UIM and LIM gaskets, no evidence of leakage, gaskets look fine.
Have my doubts about fuel side, because it's only at idle.
Realize one person had a similar problem solved with a new PCM. Not sure I'm willing to go to that expense.
Any ideas are welcome. I've chased most of the similar problems in the forum.
Rough idle (probable mis-fire) at start up and after the car warms up. Most prevalent when A/C is turned on (whether heat or AC). Worse on humid days. Only check engine light has been 1 occurance of "misfire on cylinder 3 during first 1000 revolutions". No other codes.
Here is what has been done so far: New plugs, wires and ignition coil. Replaced IAC and the PCV elbow hose connecting the UIM (clearly the PCV hose was bad. The ignition wires were also bad and arcing. Had the UIM off and checked UIM and LIM gaskets, no evidence of leakage, gaskets look fine.
Have my doubts about fuel side, because it's only at idle.
Realize one person had a similar problem solved with a new PCM. Not sure I'm willing to go to that expense.
Any ideas are welcome. I've chased most of the similar problems in the forum.