I have a 1996 Dodge Stratus ES with the 2.5L V6 with the autostick transmission. When the car is started cold, everything seems normal. After driving for some time, when I put it in park or neutral, the engine surges. The “check engine” light, when tested with OBD II scanner, gave the P0123 code for the throttle position sensor, which was replaced and cleaned to remove soot. It still surges now, although to a lesser degree. What needs to be done now?

 

TPS. Replaced, or Cleaned? Which did you actually do?

Vince

 

The TPS was replaced, and the area around it was cleaned with B-12 solvent.

 

Running fine when cold and shifting to bad will most often be a failing sensor. When you start your car, the onboard computer ignores most sensors and runs ind a pre-programed mode until the temps come up. It then starts using sensor data to adjust itself accordingly.

I take it the SE Light is out now?
Without error codes, is there a chance you filled with bad gas?

I might suspect the 02 sensor, but would also think you would see a code if it was that bad.

Perhaps a plugged cat?

V

 

You can try an IAC motor, or maybe it just needs new plugs, or you could a have a coil going bad

 

I took my Dodge Stratus to a licensed mechanic who originally thought that the MAP sensor and the TPS were in conflict, and since the TPS was replaced, the MAP sensor was the problem. The MAP sensor was replaced and did not remove the problem. Mechanic’s suggestion was that the main computer should be reset. Took it to a Dodge dealer who wants $100 to do a diagnostic on the main computer and suggested that the whole computer needed to be replaced [$300-$400, plus labor]. What is your opinion? And, if it needs to be reset, what should be the appropriate fee?

 

Is the check engine light still on now? If so what are the codes?
The computer (PCM) can be causing the problem, but so could a dozen other things. Its hard to diagnose without knowing what's happening to this car. If the dealer does the work, get the estimated price up front. Then you wont be charged any more if it turns out the computer didn't fix the problem. They will most likely keep diagnosing until they find and repair it without charging you more than the original estimated price. If the computer cost $400 the labor may only be about 2 hours shop labor time.
If the want to Flash (not reset) the PCM, its much cheaper than buying a new one.

Here are some TSB's you should ask the dealer about...

TSB # 18-01-98 SUBJECT: MIL Illumination with Hex Code $3E, Possible Sags/Hesitations/Rough Idle

TSB # NO: 18-08-97 SUBJECT: Sag/Hesitation on Acceleration, or Engine Miss

TSB # NO: 18-020-01 Bad EGR valve