1994 F150 5.0 with 4r70w. Started out as transmission downshifting at random when running along 55-60 would shift back to 2nd I think. RPMs indicated as so. Did these about 3 times then it started to not upshift unless I cranked it out (1-2 shift at 30mph) I have replaced the TPS, cleaned MAF, changed TRS on trans. Now shifts up thru the gears fine but has no kickdown when accelerating in OD or drive if I turn off OD. If I slow down enough for it to kick back to drive it will accelerate. Any ideas.

 

Any EEC codes? Is the speedometer and odometer working?

 

Had some codes before 121, 123, 157,212,334,452 tested TPS it had low signal voltage so I changed it out. Speedo and odometer are working fine

 

Clear the codes and see which ones come back.

 

Thanks glc. codes were cleared. Scanned again this morning after letting it warm up and got a 122 again. Tested TPS and signal voltage was only .2 and went to .3 when I open the throttle. Could I have gotten a faulty TPS? 122 was the only code I got.

 

Either that or you have a wiring problem.

 

Discovered I did not have ground at TPS . Ran a temporary grnd to battery and seems to be doing ok after short test drive. I will have to find the reason now and see about fixing the cause. Thanks for your advice glc.

 

Check your ground straps between the engine and body.

 

yes, I will check and clean all grounds, thanks