90 deville trouble code e 31 and e 52
 

I took a road trip to kansas city from wichita kansas . My car ran great the way there and the weekend i was there. On the way back my car started loosing LOTS of power and got 9 miles to the gallon.I also sometimes i could get the car up to 40 sometimes it would not go over 20 no matter how much you push the gas. My car will not hardly idle pretty much you have to keep your foot on the gas pedal to keep it idling. I pulled the codes today and i got E31 shorted map sensor signal and e 52 pcm memory reset. What do these codes mean is my map sensor bad??? or do i have a short in the wiring somewhere? what does e 52 mean?? I have done full tune up on this car, replaced ignition control module, and last night i replaced the TPS with no changes. Someone please give me a hand here i need to get back on the road. Thanks

Man these forums are dead! When i had my blazer i never waited over an hour for a reply on their forum. Someone please give me a hand here.

Check for restricted cat conv. and fuel pressure.