My F150 supercrew 4x4 with a 5.4 V8 has started running very rough when I accelerate to go up hills. Its so rough the truck shutters real hard and at this time the check engine light comes on. When I let off the throttle it smooths out. When I'm on flat surface I cruise along like shes a champ. I changed the spark plugs and one coil on the #6 cylinder (per ford garage test) also my fuel filter. Any help on this would be appreciated. Thanks

 

What year is the truck, what are the trouble codes, and what brand spark plugs did you use?

 

2004 I dont know my trouble codes and the sparkplugs were platinum shoot I'm having a brain fart but they are the same ones that were in there (fords brand). The engine light stayed on for half a day then went out.

 

Go get the codes read. Parts stores such as Autozone read them free except in California.

You may need more coils.