SKYWAYmech

I have a 2005 F-150 5.4L. The dealership I got it from just put a new engine in it before I got it. Now when I get on the throttle is starts shaking and losing power. Engine check light flashes. A/C stops blowing cold air. Then it goes away. Engine codes is number four cylinder miss fire. It is happening more often. Coil or injector? Only has 30,000 on the engine. Used air to blow out around coils to see if there was anti-freeze in the hole but came out dry. Need some help.

Martian

Swap coil #4 with a coil from another cylinder, clear codes, see if the problem moves to the other cylinder or stays on #4.

j.digiacomo

my 04 5.4L ate plugs and packs every couple years. CEL and bucking when throttled. i'd just replace them all while you're at it.

techrep

iTrader: (1)

Yeah..Ford probably use all the old COP's for the new motor.. do what Martin suggested to troubleshoot...

John Sweeney

I had the same problem on the same cylinder got on amazon and bought a $40 set of coils, and it was problem solved. well that was after i checked the code of course.