I have a 2001 f150 with the 4.6 and it has 181,000 miles and my truck was having a miss fire and they did the test on it and all 8 cylinders where miss firing. I had my spark plugs changed at 100,000 miles. I have a custom tune, ported throttle body and intake elbow and the gotts mod.

 

How long ago did you flash it? Go back to a stock tune and see if you still have all cylinders misfire. Sounds like a PCM error.

 

do you think I need a tune up?

 

I had flashed it over 2 years ago

 

What do you consider a tune up? Ive never heard of all 8 plugs or all 8 cops going bad at once. Flashing it back is free and only takes a few minutes.

 

spark plugs and coil boots

 

I'd put my life savings on them not being your issue.

 

should I try the canned tune?

 

Stock.

 

my engine light never came on for the miss fire and felt like a low miss fire on coil plug. is there a way I can test it ?