Guy at the parts counter gave me a warning about throttle bodies I ignored

I was at a local AutoZone in Tulsa about 6 months ago picking up some spark plugs when this older guy next to me starts talking about the 2018 F150 I was driving. He asked what mods I had and I told him I was thinking about a bigger throttle body. He just shook his head and said don't waste your money unless you've done intake and exhaust first. Said the stock one flows fine up to about 400 horsepower and a bigger one just messes up the throttle response on a daily driver. I figured he was just some know-it-all so I dropped $400 on a BBK unit anyway. Installed it that weekend and my truck felt worse off the line. Idle was rough and it hesitated when I stepped on it. Took me 3 days of messing with the tune to get it barely drivable. Had anyone else had a tuner tell you to skip a part that seemed obvious?

3 comments

3 Comments

the_cameron19d ago

Jumped in with the exact same thing on my old 2017... spent three weekends chasing a stumble that was worse than stock. What nobody told me is the throttle body angle on these trucks is super sensitive to air velocity changes. The PCM learns around a stock bore, so when you open it up the air slows down and the computer gets confused. Ended up putting the stock one back on and it ran better than ever. Sometimes the engineers actually got it right for daily driving, even if it feels boring.

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thompson.nathan17d ago

Wait wait wait... three weekends?! Dude that is absolutely insane lol. I can't believe you went three full weekends on that thing. I did ONE weekend with a cold air intake on my '15 and almost threw the whole truck in a lake. The PCM learning thing makes way more sense now too, I never thought about how the air velocity changes would mess with the adaptive learning. That's honestly wild that it took you that long to figure it out though, I would've given up after the first Saturday.

claire_ramirez19d ago

Honestly that's exactly what happened with my '16. Threw a 87mm throttle body on it and spent a month recalibrating the pedal feel before I gave up and went back to stock. Ngl the truck ran smoother with the factory part and that drove me nuts.