Hi, I drive a 99 5.4L V8 F150 with an automatic transmission. I am having two issues when driving.
First Issue: My truck cruises at constant speed or even slowly accelerates like the cruise control is on. I ruled out the cruise control by disconnecting it at the throttle body.
Second Issue: When I accelerate at slow speeds (15 -45 mph) the engine over revs to about 3500 rpm before it will change gears. Yet if I let off the accelerator before it reaches 3500 it will shift just like letting off the clutch on a manual transmission.
These problems have slowly gotten worse. I think its the tranmission but I am open to any suggestion?

 

Hi try the throttle cable make sure it not sticking. on my 2001 it was and sounds like same symptoms. Spray it with dry graphite and see if it helps.