My LeSabre will idle very roughly for weeks but will start without a
problem. Every few weeks after being driven for several miles and at
operating temperature it won't restart for half an hour or so. It
cranks OK but just won't start. When it finally does start it runs a
lot smoother and seems to have far more "pickup." (Another possibly
unrelated issue is a very loud metallic bang noise that can be felt
and heard towards the middle of the car. This usually happens while
idling at a stop light or a few seconds after shutting it off. I can
actually feel it in the floorboard.)
This car has had several new PCMs, coils, plugs, wires, sensors,
alternators, EGR, PCV, etc., etc., since I bought it two years ago. I
took it back to the shop this evening because they couldn't figure out
what was wrong last few times and left the ticket open. The shop
called today to say that the fuel system checked out OK as did the
ignition system but they think it is ignition related. They just
don't know where or what.
Meanwhile, I've practically rebuilt this car. Does anyone have any
suggestions? I'm at wits end. It's a very well maintained 1994 Custom
with under 92,000 miles. A friend mentioned the Pass Key Anti Theft
system,, that maybe the key has gone bad but that doesn't explain the
idle smoothing out after a no-start or the noise.
Thank you for your help!