I have a 2000 F150 5.4 w/ 132,000 miles. In order to wake my sluggish transmission up I ordered a SuperChips 1715 from Mike Troyer. I am using the 87 tune. Before the chip, whenever I floored my accelerator, the transmission would take forever to kick down. Sometimes it would kick down immediately and sometimes hardly at all. The chip helped a lot with this but I am still occasionally suffering the same problem: Erratic kick down. For example, the other day while doing about 20 mph, I floored my truck and it didn't kick down at all. However, this morning while doing about 20 mph, I floored it while merging on to a bridge and it kicked down enough where I thought the transmission was going to come out of the truck!

Could my TPS be causing this? I have scanned for codes and nothing shows up. Should I try installing a new TPS or would this be wasting money? BTW, I checked the TPS voltage at idle and it was near-perfect (.98 VDC if I remember correctly).

 

A faulty TPS would not cause this...it has nothing to do with telling the transmission to shift.

The times when you floor the throttle and the tranny doesnt shift, does the truck accelerate or does it just kind of do nothing?

 

A bad TPS would cause other drivability problems than just the down shift problem because it's signal is used for a lot of decsion making from EGR to Cruise control to trans lockup etc plus many other program routines..
The TPS 'rate' of change and travel does initate the down shift as the only way the PCM knows what the driver input is requesting.
Inputs from the speed sensor, the current trans gear and lock up condition all contribute to a logic decision to change trans gear.
Your going to have a difficult time finding what, in the chain of events, is the cause. Could be as easy as a connector problem somewhere.
Good luck on it.

 

i had a problem where when i would ease into the throttle in 2nd gear. at about 2300RPM till about 3,000 rpm the truck would almost pause then pick back up. almost feel like fuel cut out. but i changed the TPS and it fixed my problem.

 

Thanks for the comments. Like I stated earlier, whenever it does kick down, it takes off like a bat of of H***. The chip does make this more pronounced now. However, whenever it doesn't kick down, the truck just doesn't do very much in the way of acceleration.

I merged into traffic the other day expecting my truck to easily get ahead and downshift properly. Instead, the truck fell flat on its face. Yet, right down the road I floored it in order to jump ahead of a car and to get into the next lane and it kicked down immediately and accelerated like a rocket. It's like it has a mind of its own.

If I decide to replace my TPS, should I get one from the dealer or Advance Auto?

 

whichever is cheapest