[clinebarger]

Originally Posted by bighaas79

Like I said. Not saying that it's not possible but I have literally worked on hundreds of these trucks and have yet to run into a bad coil. Can one go bad... heck ya. I'm just saying personally from what I've experienced highly unlikely. And really as far as the dealer determining it was a bad coil using a scan tool while on a test drive, unless they were current ramping it with a low amps probe and checkin primary ignition voltage waveform with a good labscope, I find hard to believe. Unless it produced primary ignition circuit codes? Even then I would be testing wiring going to the coils before replacing, because I HAVE run into wiring issues to the coils being an issue. Usually due to rubbing the harness or critters chewing the wiring up. Now if you were talking fords, it would be one of the first things I would check. I couldn't even begin to tell you how many ford coils I have replaced, and spark plugs that were blown out, or stuck in. And if you haven't changed the filter since you put the pump in a few years ago I would be checking that as well. The biggest killer of fuel pumps is the fact that the filters don't get changed often enough. Depending on how much you drive, I usually recommend yearly or 15,000 miles or so. If they are still really clear I won't change em out but if there is even the slightest restriction vs. a new one it gets changed. Why take the chance of hurtin the pump for a measly 5 bucks or so.

X2!!!! It is very rare for a coil on any GenIII engine to fail. I havent replaced one either.