help with 90 deville

I took a road trip to kansas city from wichita kansas . My car ran great the way there and the weekend i was there. Halfway back my car started loosing LOTS of power and got 9 miles to the gallon.Also sometimes i could get the car up to 40 sometimes it would not go over 20 no matter how much I pushed 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 just have a short in the wires somewhere? what does e 52 mean?? My car is a 1990 Cadillac Deville with 167,000 miles on it. I have done a 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
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Check the vacuum to the map, then replace if ok. Why the tps, and not the map?

Check the vacuum to the map, then replace if ok. Why the tps, and not the map?


I started with the tps before i got the codes off to know it was the map. I have had tps go out before on my 94 blazer and i was getting the same symptoms, no throttle response. Tomorrow i am going to autozone to have them test my map sensor, i will also check for vaccum at the sensor and shorts in the wiring. What if there is no vaccum at the sensor? Man these cadillac parts are not cheap the map sensor for my 94 blazer was around 40 dollars the one for my caddy $80.00 TPS for blazer 20 for caddy 40!! I really hope this is the problem and not the wiring or something else i cant afford to be trowing parts at this thing right now. But e31 means map so hopefully thats it. Any idea on e 52 pcm reset? does it just mean that my battery was unhooked and pcm reset or...???Thanks for your help.

52 was the battery disconnect. BTW the AZ cannot test your map, if you are relying on their advice, don't!

52 was the battery disconnect. BTW the AZ cannot test your map, if you are relying on their advice, don't!


Thank you for the advice i didnt know if autozone could test it or not. I got kind of sceptical of them when i took my tps yesterday to have it tested and they could not find the wires they needed to test it.

So i checked everywhere for vaccum leaks i have none and i got plenty of vaccum at the map sensor. I cleared all the codes on my car and drove around the block barely. Now i got only the e 30code Idle speed control motor rpm out of range. ive cleared and regot the code 5 or 6 times. I read about adjusting the ISC by pushing in plunger with thumb untill fully retracted then unplug and check for 0.60 gap. I have one problem though i can not get the plunger on the ISC to retract by pushing it with anything. Does this mean that its bad? I cant find too much about it on google. You've been very helpfull,Please help me out one more time. thanks.

If adjustable, did you adjust the tps, this can cause code 30 and skew the isc control. You cannot retract the isc by pushing it in there is a threaded plunger involved. It should not need any adjustment if not monkeyed with, this code can also be set by a rough engine or misfire at idle, as the isc cannot compensate for the engine problem. The egr not seating can cause this also, as well as a low vacuum issue. None of what you are doing will cause the car to lose power to the point you say it is, this can be a clogged cat, or low fuel pressure.