Check Engine Light

Vehicle is a 1994 limited with 4 wheel drive. Mileage is 154,000. I noticed hesitation on acceleration and no power going up hills along with pinging during any accelration so I swapped out the MAFS from my 91 and it drove great. Went down and purchased a new MAFS and it solved all the above problems but now after 15 mins of driving, the check engine light comes on but goes off after 15 mins then comes back on. I notice no performance issues during the lihgt being on. I checked all the vac lines, clamps and wires that I removed. About 4 months ago I replaced the plugs, wires, igniton coil, oil, coolant, hoses and airfilter. I have double checked the plug gaps, gas cap seal etc. Any ideas?,,Thanks

Unhook the battery for 10 minutes then hook it back up. When you change sensors the computer sees something new that it hasn't adapted to yet and can throw a code. The light will stay off after a set number of drive cycles (don't know how many) IF there are no "real" problems.