I posted yesterday about my volvo's battery taking a nosedive, and to let everyone know I did get the problem solved.. Seems the battery fried a cell due to the high heat out here.. anyways, having another odd problem.

The car will 'miss' from time to time while driving, I'm not sure on how to describe it in any other way, but the car will missfire and then stumble really bad, almost like the fuel flow is cut off, or the spark is lost and MOST of the time the car will stall. (And not restart untill the ignition is turned off and then back on again.)

This also happens at idle as well, but instead of stalling the RPM drops really low for a moment (400-500) and then shoots upwards towards the 3,000 range before dropping down and finally leveling out at 900.

And finally, after long periods of running (Note the first two problems are random, but growing more common with each day..) the idle will change from it's usual 900rpm to about 1,500-2,000 and stay there. Shutting the car off will solve that problem as well.

Any suggestions on what I should start checking first?

One more quick thing, I was reading in my haynes 240 book, it mentioned something about having to 'retrain' the Engine control Unit after power was lost from the system for more than 10s, but I was unsure if that would apply to my year GLT.

Thanks in advance.