i just bought a 2009 FX4, and it seems to miss when i accelerate, but it only does it when the a/c is on. my last truck was a 2008 f150 FX4, and it didnt act this way. talked to a buddy of mine with a 2010, and i didnt even bring up the missing, and he ask me if mine missed with the a/c on. Anyone else having this problem or know what the solution....

 

Right Off hand....I would not think that is normal.
these should be under warranty yet?? 10' for sure
I'd be taking them back and getting them checked

 

mines got 86,000miles, so its outa warranty, the other guys 10 is prob still under warranty, i guess he needs to take his in, and tell me what the deal is...

 

Have the plugs been changed?

 

I would change plugs
change fuel filter if more than 20,000 miles on it
clean the MAF and throttle body.