I have a 2000, F150 4x4 with a Triton 4.6L engine, automatic tranny (186000km). Intermittently, while driving, the rpm's go from 1800 to 4000. Seems to happen when shifting from second to third. seems like tranny slipping. Dealer rebuilt tranny. Problem still present. Engine also will sometimes stall while driving (never while idling). Engine is also misfiring when this happens. Service engine light does not come on usually.(Came on once showing code for multiple misfires). Dealer says electrical problem but unable to find cause. Intermittent but getting worse. Checked fuse panel under hood and dash for corrosion, shorts, etc. Checked all electrical connections I could find. Any thoughts on what the problem could be???

 

Checked the spark plugs?
Thats where I've found most of the misfire problems when it comes out in the code. I dont have any clue about the RPM problem though. I'd be angry at the dealership for giving you that vague of an answer.

 

Throttle Position sensor