An example: tonight going down the highway, on cruise, started to go up a small incline and the engine kicked into a lower gear to speed up but nothing seemed to get the speed up. Down from 57 to 43mph, I took off the cruise and sort of babied it back up to speed (55mph). It seemded to be chugging or laboring during this time.
Other times, just driving in the city, it doesn't have the power when I give it the gas. It labors. Perhaps not getting enough gas. It doesn't always do it. At times everything seems ok but then without a warning, it acts strange.
It's not gas line freeze up. (Added isoproyl). Added fuel injector cleaner. Transmisson fluid looks good and at proper level. 71,300 miles on Buick Regal. Not fuel filter. No obvious vaccuum leak - no sound of leaking. Engine purrs beautiful - when idling. Overall this car has been very good. No problems - just the normal tires and brakes etc. No 'engine service light' shining. Any and all ideas would be apprreciated.
Could this be caused by a malfunctioning brain (ECM)? How could I test this to verify it?