02 Sable - Rough Idle
2002 Sable DOHC - Vin "S" 80k miles. Car has been running fine. When I went to start it today it did not "catch" but I heard a single "pop" type of noise. Turned key again and it started but with very rough idle. Shut down, started again and it idled up to about 2,000 and slowly idled down to where it became rough again. No check engine light through any of this. Disconnected MAF and idle was slightly better for 5 seconds or so. disconnected IAC and engine stalled. Pulled both and very clean.
I am beginning to suspect the EGR. I seem to get no vacuum to it at any RPM. Not sure why not. However, I also occasionally hear a clunk coming from that general area. Also, on braking a second immediate pump of the pedal seems like there is little or no vacum. In a few seconds it comes back good enough for one pump. Do I have a major vacuum leak? Could that have been the "pop" I heard?
One thing I know for sure is that this is not as easy as my '66 Mustang - the good old days. Any help is appeciated.