99 park ave won't kickdown

[chrismyers72]

I have a 99 Park Ave. I recently had the intake Plenum replaced. When I got the car back the check engine light came on and the transmission wouldn't kickdown. when I slow down or stop it downshifts and shifts normally. If I Manually shift it it shifts fine. the code from the check engine light was for the throttle position sensor. I had it replaced. that wasn't the problem. I still get the same code and kickdown problem. So I had the wiring pigtail to the T.P.S. replaced that's not the problem either. Oh when I first start the car it kicksdown normally the first 2 or 3 times then it quits kickingdown and sometimes the check engine light is not on when there is no kickdown. HELP!

[HotZ28]

Did either problem exist before the UIM replacement? If not, take it back to whoever did the work and explain the problem. Evidently, you have an engine history code & transmission code.