Gen 2 misfiring badly under boost/acceleration

[farshad]

Hi all, I'm new here and I have a problem with my 2017 raptor. I owned a gen 1 for years and I just switched to gen 2 and in less than a week it broke my heart. The car is stock and the only thing I did to it before it started giving me trouble was cobb tune stage one. when I'm driving around it drives just normal, no check engine light. When I step on it, it backfires like a machine gun and if I don't let off the gas, the check engine light starts blinking and it will disappear within a minute and it drives fine until i step on it again. I used the cobb port and find out cylinder 2 is misfiring. I thought it could be plugs or coil. replaced them on cylinder 2 with cylinder 1, same results on cylinder 2 still. I figured if it was them it should change to cylinder 1, but no luck. I also change the tune to stock and still does the same thing. Has anyone experienced such a thing? Any ideas i could try before taking it to dealer to give an arm and leg for it?

 

[smurfslayer]

I’d suggest a compression test. If you had a good running truck before the tune, my bet would be the boost went a little over the top. It to be a doomsayer, but I would not be expecting an inexpensive fix

 

[raptor556]

I think you did the common sense thing first, checked the plugs and coil.

Now I doubt there is any sense in guessing online. Get it to a pro.

 

[Therock88]

As others suggested...Likely going to need to have someone look at it, as it won't be correctly diagnosed on the internet/Forum.

If it runs good when driving easy, and starts acting up under acceleration...That usually suggests plugs/coils in many cases, especially if it occurs in mid-range. Another thought, since you said it starts flashing CEL while you are in it...May be O2 sensor/cat related. Those seem the most obvious, but going to need to get someone to actually look at it. You may also check by monitoring the post Cat O2 and see if it is steady or going all over the place...another sign it (or that Cat) may be bad.

Good luck.

DC

 

[Mister Pinky]

Reflash to stock and see if the issue persists.

 

[isis]

^^This especially. Are you running the right tune for the gas available to you?

 

[Muchmore]

Guys, the final sentence in his post says he returned it to stock and the same thing still happens. I was having weird rough idle and cut out's while accelerating so I started by replacing the plugs with a pro-gapped set from Livernois and it totally took care of me. You could have a set of just worn-out plugs and only one cylinder is more sensitive to it for some reason. IF you can't verify the plugs have ever been done I would start with a new set, cheaper for you to do it than the dealer during diagnosis.

 

[Mister Pinky]

Guys, the final sentence in his post says he returned it to stock and the same thing still happens. I was having weird rough idle and cut out's while accelerating so I started by replacing the plugs with a pro-gapped set from Livernois and it totally took care of me. You could have a set of just worn-out plugs and only one cylinder is more sensitive to it for some reason. IF you can't verify the plugs have ever been done I would start with a new set, cheaper for you to do it than the dealer during diagnosis.

Whoops. Didn’t see that. I agree with your assessment. Colder plugs are the next best bet. And how many miles are on this truck, OP?

 

[smurfslayer]

Danny’s point is a good one, maybe try with fresh / new plugs, well and properly gapped For the tune.
good catch

 

[Muchmore]

Danny’s point is a good one, maybe try with fresh / new plugs, well and properly gapped For the tune.
good catch

Easy stuff is easy, do it first!