When driving on the freeway at 60 and I push the gas peddle to the floor my truck won't accelerate. It will downshift, the transmission sounds like it is revving up but the RPMs aren't maxed out. It has progressively got worse. Taking off from a light if I push the gas peddle 1/4 the way down it bogs down. When that happens if I push the gas peddle half way it will downshift but still won't accelerate. If I push the gas peddle down about an inch and hold it there it will accelerate normally. When it is 40 degrees outside it runs like a scalded ape. It seems to have these issues when it is above 70 degrees outside. Has anyone ever had this problem and if so what did you do to fix it?

 

Probably your TPS or you might need a new gas pedal assembly

 

Try this: key in the ignition turn to ON position but don't start engine.
After all the check lights and chime go out press the gas peddle to the floor slowly and then let up, turn key to off position, now start the truck and go for a ride and see if this has fixed your problem, if not you probably need a new TPS on the throttle body.