My mother in law has a 2004 LeSabre, white, about 135k miles on it, 3.8 V6, had tranny rebuilt about 2 years ago. She doesn't drive, she'* disabled, she bought the car for us to basically drive her around in. Has been clean, reliable car, in good shape.

Last little while, we've been having trouble with it (a.) sporadically idling very high, it'* worse when the engine gets warmed up; and (b.) rough, delayed shifting, which we figured was an offshoot of the idling issue.

It finally threw a Throttle Position Sensor code, and we had the TPS replaced. It did not fix the problem, we've just been driving the thing and nursing it and dealing with the high idling and rough shifting.

Last week it threw another TPS code. We took it to a mechanic yesterday, top flight guy who works on my own cars, he examined the thing and found that the upper intake manifold was leaking antifreeze down into the sensor, said that was screwing the sensor up. After he replaced the manifold and did a pressure test, he found an additional coolant leak from the elbow pipes in front, those were replaced too. The TPS also was replaced, total cost $524.

Picked the car up today ... and it'* still doing the same @#$%^ thing, which is symptomatic of TPS issues.

Anybody got any ideas what might be going on here, or could give me some direction here? I've had done all I know to do with this blasted car, and my mother in law is not happy after shelling out that much cash and it'* still not running right.

I'm curious if the TPS was installed correctly.

Here'* a good video that instructs the proper way to install them...