2000 F150

[Pooh]

Its got a 5.4 129000. Been good to me! Its got a miss. Guessing its time for plugs and coils. Had one fixed last summer after blowing on me. Other than that, is been good. My question is. How long our bad does a miss have to be before it actually throws a code for the check engine light?

[Scott K]

On that era Fords? A dead miss, and you would be lucky it set a code. Mode 6 data would be the best way to retrieve which cylinder is missing, but on a 2000, you pretty much need a Ford scan tool to access it. 2002 on up, and most scan tools can retrieve mode 6 data from the vehicle.

When does it miss? Light throttle, about 40-55 mph?

[Pooh]

Its been real hit and miss (no pun intended) on when it misses. Today anywhere from idle to highway speed. it has progressively gotten worse. Started when you where around 50 going uphill. Today it was in town, on the highway and at idle. On the highway when I got on it to accelerate back to 65 I could feel the motor plane out with all cylinders firing and kick back to to running on 7. I just figured it should throw a code by now. Guess its time to get it to the shop before it gets even worse