Surging RPM

[bostby70]

I have a 94 Grand Prix 3.1L and here is the problem. It just seems to happen randomly, when it does happen i am just cruising down the road and all of the sudden the engine will surge from 1500 to 2100 it will do this several times and each surge will will last for a second or so. I have replaced the fuel filter and it was better for about a week and then all of a sudden it started to act up again. Also put new plugs, new wires, and new ignition coils in about a year ago. any advice, suggestions, or solutions would be greatly appreciated.

[Sigmund1965]

Are you loosing coolant ( not leaking, just seem to have to add some every now and then). Pop the hood and listen for a sucking sound ( like a vacuum leak) If so it could be your lower intake manifold gasket.

[dreyes78]

I had surging rpm problem recently. Changed the Throttle Position Sensor and all is fine. Beware, some people might say that Throttle Position Sensors rarely go out. Mine went out at around 75,000 miles. Cheap(about $34-45) and easy to fix (1 connector and 2 screws). Hope this helps.

Dan

[Ridenour]

Your wire boots may be loose. I had the same thing happen after changing my plugs / wires, and I went home, pushed down on all the wires really hard, and the problem was gone. Your wires might just not be properly seated.

[GTP Dad]

Clean the mass air flow sensor. Simply spray it with cleaner allow to dry, spray it again and should cure the problem. On the 3.1 it is located in the incoming air stream from the air filter ahead of the throttle body.

[bostby70]

thanks guys, i will try those things tomorrow, really appreciate the tips

[troy1]

just fix my 95 GP it was doing stuff like that. the reason why was the was no software in the computer cost 75.00 to reflash it!! Check it out

[GTP Dad]

How did you manage to lose the programing from the computer that you had to have it flashed again? Computers are read only and I really have never heard of one simply losing programing without some outside help.

[troy1]

dont ask me but there was not software I watched the guy reflash it. I bought the car with bad tranny OH'd it at the shop ran like crap for a while got real cold out ran worse took it to a engine shop didnt find anything we both decied to reflash the computer. Come to find out it was a junkyard computer so I am waiting for it to loose the programing again