JC327

2004 FX4 5.4 90K miles

I just bolted on a flowmaster exhaust last week, now I'm getting a rough jumping/missing at about 50 mph. Jumps and bucks like hell.

Did I create an exhaust leak which might create this condition? Just a coincidence?

I've searched this forum and have some things to check out, but the exhaust is the only thing I've changed.

Would appreciate any input.

Thanks! Jim

GATORB8

Any codes?

Squirtbottle09

Sounds like you need to change your spark plus.

JC327

I've been looking into a spark plug change.
Would this be a symptom of bad plug or plugs?
I track gas mileage, but I've only had the truck for a month so I can't detect any downward trend.

Thanks! Jim

GATORB8

Make sure you look up TSB 08-7-6 before attempting the plug change.

dase520

it your coil packs and plugs mine just started doin that and i took it in to ford to get a full diagnosis on it cuz i had no check engine lite or anything and turns out its the number 4 and 5 coil packs but i dnt know which coil pack is 4 and 5 so they just recommended to change the plugs as well but im thinking of doin the job my self.