When driving the car around 50 MPR the car will shift to 4th and back to 3rd once or twice before it shifts to a gear and stays there. If I am going 60 + it won't do it as often. I am wondering if this is a computer tuning thing or something else. Tranny fluid is good. The comp was programmed by PCM for less.

 

Ask yourself this question.

Did the problem originate immediately after the PCM program was installed?? If so ... there is you answer.

If not, then perhaps a solenoid or something else is going away in your transmission.

Hope this helps

LWM

 

your question can not be answered since the car has a new 383 stroker, new program, new Tranny. All was replaced to get the car back on the street. I have no clue where to start.