I got a 2015 3.5L Eco Boost with about 217,000K and it was running perfectly until recently. A few weeks ago the truck started misfiring, got the general misfire code and the cylinder 3 misfire code, so we gapped all the new spark plugs (6 months old) the issue went away for a few days. then it came back with the same codes, so we replaced the battery (it was on its way out anyway) cleaned the throttle body, and last night we got P0200 fuel injector code and P0103 Maf code.

Has anyone else had a similar circumstance? the code chase makes me think ECU but I might be getting ahead of myself.

thank you

 

Wild guess would be that you're losing a ground somewhere or a short is starting. Wiring problems. The last two are circuit codes.

 

I have a 2014 3.5L Ecoboost (162K mi) and I had a misfire happen twice now but it went away. Both times it happened I was flooring it to pass but the engine continued to run and accelerate. issue went away about 30-45 sec after returning to normal speed (~60 mph). Checked code next opportunity and got the same P0303 misfire cylinder 3. I used Autozone's reader and it recommended a new spark plug and coil pack. My question to you is did you change all the coil packs when you changed the spark plugs?

My suspicion is that it is the coil pack rather than the plug. I could swap it with another one and see if it moves to that cylinder.

Other question to others is: if I change my coil pack should I change them all and if so should I change spark plugs??

 

Yup...coils...every time.

Check your coils.

 

When I said I got new plugs, they were NGK plugs. I got the plugs from FORD and all the problems went away.

In summary, get your plugs from ford. I've never had NGK let me down, but I suppose anything is possible.