Engine Performance problem
1987 Ford Bronco 6 cyl Two Wheel Drive Automatic 120, 00 miles
My Bronco just started doing this suddenly last saturday after a 30 mile roundtrip. Ran fine for the trip. An hour later I got in it to go to the store and I notice was now dramatically losing power no matter what speed I was going. The RPM's would start out normal, then drop dramatically (500-1000 RPM's) for a second or two, then shoot back up to full operational RPM for another 10-30 seconds. This cycle repeats continuously, even while sitting still and idling. It needs to warm up for a minute or two before the cycles starts, but once it starts it cycles continuously.
Yesterday, I drove it 40 miles like this and noticed I'm consuming double the gas I normally would.
I took it to my mechanic and his only solution was to replace the MAP sensor, which did nothing. He said there were no air leaks. Not sure if he checked the fuel pressure regulator or not, but he seems he had too if he checked for leaks.