tryitout

Alright fellow members, I need some help....
I have an 09 FX4 with 150000 miles on it
Started out truck would buck or stutter when engine was lugging such as OD on a slight incline before downshift. Everything I read on this on other forums said it was probably a COP going bad. Figured high mileage truck, I would just change all of them with plugs. Changed all with Granatelli coils and NGK platinum plugs. Truck ran good for 2 days. Now it is missing bad AFTER engine gets warmed up. Seems to only miss under load. At idle it seems to clear up. All coils are plugged in good and all are getting negative trigger signal at harness at idle. Can really test under load condition. Any ideas?

FST150

Could be a really dirty mass air flow or a bad O2 sensor also

tryitout

I was just able to put a scan tool on it and I am getting codes 351, 352, 354, 355, 356, 357, and 358. It seems hard for me to believe 7 out of the 8 new coils are bad. Could it still be MAF or O2 sensors?

Mr_P0L0

I have heard that the brand of coils you are using can go bad fast.

RLXXI

3 digit fault codes are OBDI

Your truck is OBDII you need to clarify because what you state makes no sense.

Cylinder misfire codes are:

P0300 Random misfire
P0301 Cyl 1
P0302 Cyl 2

Etc

.

Snowflake

He didn't put the p0 in front it coil codes

RLXXI

Look again at what they posted, 351, 352 etc???

Those are invalid codes, if they wish to get help they need to make an effort to give accurate information.

.

Fudd757

On some models...especially my 03 the coils went bad regularly....in fact our company mechanic ended up changing them all...the symptoms were missing/ stutter under load. My 10 hasn't had the same problem.

tryitout

They may all be po codes. My MAC scan tool (6 years old) only shows digits. They all say Primary/Secondary circuit failure coil X (where X is a letter).

cthusker

changed out my 06 coils 3 times… once almost back to back!! The NEW coils were in fact BAD! Finally got a set that lasted a couple of years and missing/stutter under load stopped happening.

I also found it hard to believe NEW COP's were bad almost from the start but they were. Not saying for sure that's the problem but it sure sounds like the problems I had with my 5.4……..