1995 Lesabre motor surging and dying at stops

[99GTfakeSnake]

I recently purchased a 1995 Lesabre with 120,000 miles and I have noticed some old behavior. Randomly the motor will rev up very high (there is no tach but I would guess 4000+ rpm) whether the car is in gear or not. I have found no certain thing that gets the motor to stop surging so high but when it does surge it stays at a constant, yet very high, rpm level. The other issue is several times when coming to a stop the car will die. It starts right back up but I am wondering if these two issues are related. If anyone has any advice it would be greatly appreciated.

[HotZ28]

You need to check the TPS for proper voltage and "spring return" action. The TPS, is simply a potentiometer used to vary voltage. The best way to check the voltage is with a scanner, but if you do not have access to one, you can use a DVM. The TPS WHITE wire, is the PCM reference signal and should measure 5.0V with ignition on. (Engine does not need to be running) The BLUE wire will show variable voltage from a closed TB position, up to WOT, where it should measure 4.0V - 4.5V max. The BLACK wire is ground.

[99GTfakeSnake]

Ill check that in the morning if I can find my meter.. Would that be the possible cause for the surging and the stalling?

[HotZ28]

Actually, the function of the TPS, is to tell the PCM where the throttle body blade is located. Then the PCM uses this information, to determine the RPM, fuel curve etc. If the TPS does not move with the TB opening, or is stuck at a partial throttle position (with the throttle blade closed), s-tag happens!

Also, something worth mentioning, would be a huge vacuum leak that could make the engine respond in the manner you described. For example; If the brake booster vacuum line was loose, cracked or missing from the fitting, you may get the same, or similar symptoms.