2000 6.0L runs rough and stumbles

[bighaas79]

I'd put money that it's not coils, and if you just bought 8 of em you wasted your money. I have never seen one go bad, not that they can't, but extremely unlikely that 4 went at one time. If you did have 4 dead coils you should be looking at power supply issues before replacing coils. Personally if they told you that it needed coils from just data streams and not actually testing anything, i'd say they are just tryin to suck ya for money and don't really have any idea what they are talkin about. What are the fuel trim readings at? O2 sensors responding properly? Have cats been checked to see if they are coming apart and plugging exhaust? Maf sensor readings and map/baro reading would be helpful as well. Would also check iac as well.

[heavychevy77]

Come to find out.....I had a couple cooked plugs and a bad spark plug wire. I changed the plugs and got the one wire replaced and this truck runs better than it ever has! The wire was broken internally and it was arcing to the head. This thing is a beast!
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[fxdxharley]

Originally Posted by bighaas79

I'd put money that it's not coils, and if you just bought 8 of em you wasted your money. I have never seen one go bad, not that they can't, but extremely unlikely that 4 went at one time. If you did have 4 dead coils you should be looking at power supply issues before replacing coils. Personally if they told you that it needed coils from just data streams and not actually testing anything, i'd say they are just tryin to suck ya for money and don't really have any idea what they are talkin about. What are the fuel trim readings at? O2 sensors responding properly? Have cats been checked to see if they are coming apart and plugging exhaust? Maf sensor readings and map/baro reading would be helpful as well. Would also check iac as well.

Coils are known to go bad on these. i had to replace one do to a mis fire under load. had the dealer scan it during a test drive. all though never heard of 4 going at once. I still have minor issues with rough idle and some hesitation. Ive changed and checked everything i could. i just deal with it now. its got 180 k

[bighaas79]

Originally Posted by fxdxharley

Coils are known to go bad on these. i had to replace one do to a mis fire under load. had the dealer scan it during a test drive. all though never heard of 4 going at once. I still have minor issues with rough idle and some hesitation. Ive changed and checked everything i could. i just deal with it now. its got 180 k

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.

[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.

[fxdxharley]

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.

The tech at the dealer pluged in there obd scan tool and we went for a drive. code for mis fire on cyl 2 came up under load. he then swapped that coil with a different cyl and the same code came up for that cyl. put a new coil on and code was gone. So i tend to believe the tech and my own eyes seeing the codes. all the wiring is fine, plugs are new, wires are new. maybe a new filter wont hurt but i dought that is my problem.