Bad Misfire- HELP...

[Lazzman]

The problem started when I had my plugs re-gapped to .065 for the screamin demon coil. When I first got the truck back I noticed a bit of a misfire at idle, it did not seem that bad so I ignored it.

Two weeks later, after a night of driving the truck hard. I start it up in the morning and cruised down the road, all of a sudden I get a huge misfire and the check engine light goes off.

I Take it to Autozone and their scanner says cylinders 1 & 4 are misfiring. Replace all of the plugs with new ones that are properly gapped at .054. Still have the misfire.

Contact the guy who sells the coil, he says that some people need to buy an extended coil harness for the demon, as the old one is not long enough and could cause misfire under the added stress.

I replaced the harness tonight with a brand new motorcraft one that is longer. Fire her up and the misfire is still there, though it is not nearly as bad. Mostly at idle and around 1500rpm's. Drove the truck for 10 miles and no engine light.

Now what do I do? It seems I have two choices the coil or the wires? I did drive the vehicle for two days with the misfire, maybe the coil malfunctioned. It could also be that the person who re-gapped the plugs pulled the wires off by the wire and not the boot, ruining the wires.

I need some direction, from anybody willing to help.

Thanks

 

[celly]

Duude. You have BAD luck.

 

[Jakee]

The problem started when I had my plugs re-gapped to .065 for the screamin demon coil. When I first got the truck back I noticed a bit of a misfire at idle, it did not seem that bad so I ignored it.

Two weeks later, after a night of driving the truck hard. I start it up in the morning and cruised down the road, all of a sudden I get a huge misfire and the check engine light goes off.

I Take it to Autozone and their scanner says cylinders 1 & 4 are misfiring. Replace all of the plugs with new ones that are properly gapped at .054. Still have the misfire.

Contact the guy who sells the coil, he says that some people need to buy an extended coil harness for the demon, as the old one is not long enough and could cause misfire under the added stress.

I replaced the harness tonight with a brand new motorcraft one that is longer. Fire her up and the misfire is still there, though it is not nearly as bad. Mostly at idle and around 1500rpm's. Drove the truck for 10 miles and no engine light.

Now what do I do? It seems I have two choices the coil or the wires? I did drive the vehicle for two days with the misfire, maybe the coil malfunctioned. It could also be that the person who re-gapped the plugs pulled the wires off by the wire and not the boot, ruining the wires.

I need some direction, from anybody willing to help.

Thanks

Lazz - Go for the easy solution fist; the plug wires. Check each one, one at a time. Make sure there fitting snug; you might have to crip the ends if they come off real easy. After you mess with one, start the truck up. go to the next one. Once you've went thru and verified there all good, then start blaming the coil. make sure the connector to the coil is all the way in!! it can trick you.

 

[Lazzman]

Thanks, I will give it a try.

I am thinking of changing my board name to bad luck schleprock.

 

[celly]

Thanks, I will give it a try.

I am thinking of changing my board name to bad luck schleprock.

Wowzy, Wowzy Woo.

 

[aldive]

Lazz, since you suspect the coil pack, why not simply swap back to the stock coil pack and see if the misfire situation is duplicated?

I also run the SD coil pack and have no problems whatsoever.

 

[aldive]

Lazz, did this misfire occur on your recent dyno session at high RPMs also?

 

[badgett]

Change your gap back to the original specs. I know the coil says to go .65 but i bought a new coil that did the same thing. When I changed the gap back to specs it stopped misfiring.

 

[BrooklynBay]

Restore everything to its former condition, and reset the PCM. Install each modification one at a time until you get this problem again. This will tell you what part is causing the misfire.

 

[Lazzman]

Aldive, it did not seem to be misfiring on the dyno but I was not driving it. When I got the truck back that day I did notice a slight loppy misfire at idle but nothing in the upper rpm ranges.

I did not swap the Demon pack because I don't think that is it. Al, ToddZ told me that a condition can occur because the Demon coil has the connector on top. The stock wire harness is not long enough to reach so some people stretch the hell out of it causing a bad connection. Coils usually don't go bad, plus it has been raining up here and I have no garage, I decided to get it scanned.

I'm a manager at a Logistics company, I had one of our mechanics scan the engine light with a Ford factory scanner. He said it was showing misfire on cylinder #1.

Over the weekend I replaced all of the plugs with new Brisk Racing plugs. They are the one's that were developed with Lamborghini and that Roushe uses on his RushStangs. Great plug and it has no side electrode so no gap needed.

It seems that the speed shop damaged my 6mo old Magnecore wires when they were re-gapping the plugs. Guess that is why that plug wire had carbone all over the boot.

It seems I need a new plug wire from the coil to the #1 cylinder. The #1 cylinder is the hardest to get to and the one that is on the passenger side rear of the engine.

Help please.

 

[aldive]

Coils usually don't go bad,

Not necessarly true. Did you test the coil?

Over the weekend I replaced all of the plugs with new Brisk Racing plugs. They are the one's that were developed with Lamborghini and that Roushe uses on his RushStangs. Great plug and it has no side electrode so no gap needed.

Lazz, stay away from gimick plugs and install some Motorcraft ones.

It seems that the speed shop damaged my 6mo old Magnecore wires when they were re-gapping the plugs. Guess that is why that plug wire had carbone all over the boot.

I assume they replaced the wire(s) that they damaged?

Good luck resolving your issues.

 

[Lazzman]

How am I going to prove that they damaged the wires??

They will never admit to that.

 

[BrooklynBay]

How old was the first set of wires?

 

[aldive]

How am I going to prove that they damaged the wires??

They will never admit to that.

Did they install the wires?

 

[Lazzman]

No the wires were purchased about 8 months ago.

All these guys did was re-gapp the plugs to .065 for the Demon coil.

I think they may have snapped the wires off without grabbing the boot.

The two cylinders I had trouble with #1 & 4 are both at the back of the engine and hard to get to.

I suspect that the mechanic grabbed the wire, pulled it and popped the boot off. Instead of gently prying it off at the boot.

 

[aldive]

Have you discussed this with them?

 

[Lazzman]

No they are idiots...

 

[vayne]

Have you checked to make sure each plug wire is in the correct order on the coil pack? I had a similar problem to yours when I changed plugs and wires and realized i had two of the plug wires crossed on the coil.

 

[Jakee]

I've gapped my plugs to .065 and have no problems. But, it didn't do anything for performance so i wouldn't go out and re-gap your plugs.

Yeap, I bet it's the wires or the coil pak connection.