I want to thank those that can help....

I have a 1993 cadillac seville with idle and surging problems. At first start and after cooling off the car does this along with a rough shaking of the car. During the idle if I mess with anything electrical the idle gets rougher and the idle gets lower. I've changed the wires and plugs and the same thing has been going on.

If anyone an help me out i greatly appreciate it.

 

4.9l or northstar

 

im sorry its a 4.9

 

i know the code 12 means theres nothings wrong but its also pulling up code 31 when my a/c compressor turn on the car shakes not one time it fell dead. ima try sea-foam but what would be the next step if that doesnt work.

 

Possible plugged fuel injector. Try removing one plug wire at a time, engine running,to locate the cylinder that runs the same with the wire off. Then post back.

 

Code 31 shorted map signal. Do you have factory service manual?

 

thannks carnut ill try that. slowroll i dont have a factory service manual, what is the map signal for.

 

MAP sensor is main computer input for engine load. MAP sensor signal voltage effects timing and fuel control. Shorted MAP sensor,ECM, or sensor wiring can cause your concern.

 

sorry slowroll it took so long to reply.i did change my ecm and its doing the same thing. is there anyway the i can test the map sensor out. what should happend if i unplug the map sensor, and what do you mean by sensor wiring. when i turn my head lights on and put the car in motion thats when it surges as well as turning the a/c on and when the compresser kicks in it does the same thing, could this be a electrical problem

 

i did change my ecm and its doing the same thing. is there anyway the i can test the map sensor out. what should happend if i unplug the map sensor, and what do you mean by sensor wiring. when i turn my head lights on and put the car in motion thats when it surges as well as turning the a/c on and when the compresser kicks in it does the same thing, could this be a electrical problem