shescountry

I just had all eight coils replaced about a thousand miles ago. Quit skipping for about 500 miles now it's skipping worse than it did before I put new coils in. What could it be? I've heard timing chain, valves sticking or a bad coil. I'm taking it back to the shop Tuesday for them to look at it to see if a coils gone bad already. It skips so bad the rpms jump about 200-400 rpm and it back fires like hell. You get on the peddle getting on the interstate or in traffic and it sounds like a drive by. It's never been this bad!! Please help I'm a little stumped guys.

Summers22

iTrader: (2)

Did you do plugs with coils? Were Motorcraft parts used? Is the MAF clean?

shescountry

No the plugs only have around 30k on them. Haven't looked at the MAF. Talked to another f150 guy an he said his truck done the same stuff bc of a clogged cat. I'm gonna have them checked out Tuesday too.

Summers22

iTrader: (2)

How many miles do you have?

shescountry

1556xx

Summers22

iTrader: (2)

If the coils are Motorcraft and are good, then cats sound like the most likely culprit. If aftermarket COP's were used, then that may be the problem. I have had a truck with over 175K on it, and never had a COP go bad.

racecrew25

mine did that before as well....turned out to be the CPS (crank position sensor)....easy fix, took 25mins, and part was $35.....hopefully this helps

shescountry

Not sure what brand coils are in it. I'll find out I'm beginning to think it's just a bad coil and bad cats. I have noticed when I get on it and it back fires it only back fires from the passenger side.

mastercam

did exactly the same work. coils plugs..exactly the same mileage. mine doesn't backfire just misfires at all rpms. feels like the timing is off?

shescountry

Mines at the shop now. It's a waiting game from here on out. Head guy at the shop said clogged cats was a very good possibility which is where the back fire would be coming from. I barely made it to school yesterday it was skipping so bad.