Recently my 5.3L has been giving a rough idle on cold start only, no drivability issues. It starts fine, goes to 900/1000RPM as usual and after a few seconds it starts to stumble. The RPMs drop to 500 and bounces to 700 for a few seconds, 5-10 maybe. Then it slowly starts to clear out. the idle will jump to 1100 then settles down at 900 and then slowly drops as per normal warm up. Whole process from start, rough and back to smooth is under 20 seconds.
Current temps are single digits in the morning, approaching 10C. Doesn't do this except first thing in the morning. 145k km (90k miles). Recent new plugs, wires, O2 sensor (done by dealer). Also a new air filter. No CEL present.
I found other threads with similar symptoms. Those threads all seemed to have a lot of guesses at the problems and no resolutions. One thread mentioned "SAIS Valve" but I don't know what this means? I am guessing it is an air injection system? Anyone point me in the right direction on that?
Has anyone had this issue and solved it? TIA
Current temps are single digits in the morning, approaching 10C. Doesn't do this except first thing in the morning. 145k km (90k miles). Recent new plugs, wires, O2 sensor (done by dealer). Also a new air filter. No CEL present.
I found other threads with similar symptoms. Those threads all seemed to have a lot of guesses at the problems and no resolutions. One thread mentioned "SAIS Valve" but I don't know what this means? I am guessing it is an air injection system? Anyone point me in the right direction on that?
Has anyone had this issue and solved it? TIA
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