Tried a homebrew tune on my F150 and now it hesitates on acceleration. What did I screw up?

3 comments

3 Comments

Yeah, that whole 50 mile gentle drive thing is the worst part. It's because the ECU has to relearn the fuel trims for all the different load points, not just idle. If you jump on the highway and floor it right away, it's trying to adjust fuel mix with zero baseline data. That's where the hesitation really comes from. The truck is basically guessing.

the_joel1mo ago

Wait, you actually drove gently for fifty whole miles? That sounds like torture. I reset mine last month and just did the idle thing, then drove normal. The idea of babying a truck for an hour straight after a tune is wild to me. Maybe my neighborhood roads are rougher, but I'd never make it that far without hitting the gas. That relearn process seems way too fussy for something that should just work.

the_piper1mo ago

Ford's electronic throttle body needs a reset after flashing. Your tune wiped the ECU's learned air flow values. That causes hesitation like a dead spot. Disconnect the battery for 30 minutes. Reconnect and idle for 10. Drive gently for 50 miles to relearn. Fixed mine last year.