Oldsmobile/Buick Repair: loss of power check engine light, chevrolet cavlier, vacuum leak

Question
I own a 1993 Chevrolet cavlier with a 4 cylinder engine. The car seems to loose power like it is going to stall,which it does sometimes.it lasts about 10 seconds and then then the  car clears up and runs perfectly fine. The check engine light usally comes on while this is all going on and then goes off after it all clears up.. Ill drive it for about 40 miles or more and the same thing happends. I just had the computer replaced,02 sensor replaced and the map sensor and gas filter replaced and it still does this about every 40 miles or so. Any suggestions?  

Answer
Hi Walter,
All I can think of is a vacuum leak, which could be associated with the EGR valve sticking, or something in the air cond controls.
Another possibility is the gas tank forming a vacuum and starving the engine till something allows air into the tank.
Try driving with the gas cap loose, although on the newest vehicles, that will set a code.
Van
Van