2/97 f250 5,8 l auto. Shifts great when cold but after warm up you have to lift on gas to get it to shift 1to2 is really bad 2 to 3 is sometimes bad.. I thought it was a vacuum problem but this trans does not have a modulator.. is this a worn valve body? 255,000 miles update.. changed the vss .. did not solve the problem.. when pulling codes I got a 65 then code reader stops and now doesn’t initiate tests..

 

Are there any codes stored in the PCM?

 

no codes available

 

I don't know about the 97,if Mark is on here he can answer better...but my 94 5.8 E4OD was doing the exact same thing...it was the speed sensor on the rear differential...got a two wire clip and one bolt holds it on. Changed it and it had a little difficulty the first time I drove it after swapping but none since.

 

 

oe sensors are notoriously reliable and the aftermarket.. eh.. I would test it first… and verify wiring is okay before replacing it.

 

Yep... I agree... I actually broke a clip on mine trying to change it so I had to swap the plug too