A few weeks ago when the problem first occured I thought it was the catalytic converter, because I heard a exhaust noise from the driver side cat. I mean I couldn't even drive down the street, idled like crap and felt sluggish when trying to go, could hardly go 20 mph up a hill. So I finally removed the y pipe to discover the cat all most coming apart from the top of the can, best way I can describe it. So I welded it back up and it ran better.

But I noticed a slight hesitation or sluggishness when accelerating hard, like if the truck was jerking. I thought maybe it was time for a tranny flush, so installed new filter and fluid. Also replaced the transfer case fluid while I was at it. Took it for a test drive and problem was still there.

Then the other day all of a sudden the problem came back, idles like ****. Whenever you accelerate its sluggish. During these times the CEL is flashing constantly. Read the codes and its always misfire on cyl#6. I did a head gasket job couple months back, cylinder 6 was steamed cleaned. But keep in mind the vehicle has been running good since the HG job until recently. Removed the plug on #6, it was wet smelt like oil and fuel. Now if #6 was dead I don't think it would be causing the crappy idle and extreme sluggishness. So possibly two problems effecting number#6? running out of ideas..What do you guys think? Has anyone had this problem before?

 

have you checked for spark @ #6 plug wire?
loose wire @ coil?
bad wire?
bad plug?

you could try swapping wire and plug to another cylinder to see if the misfire changes

 

i've had a crappy idle with 1 cylinder out before

 

1 plug is enough to make it idle very poorly, and not accelerate well either. I just went through this with a failed #7 plug. I also just did a head gasket, new plugs installed after HG job. Decided to do a seafoam manifold treatment, and after that had misfire code on #7. I swapped the plug to a different hole, and the misfire followed. Changed the plug and it was fine.

If you've not replaced all your wires and plugs I would do that. I'm guessing you did that when you did your head gaskets?

 

Checked for spark at #6, has spark. Tried to feel if the wire was loose at the coil, kind of hard considering I have big hands and have the secondary air injection. Also put a timing gun on the wire to see if the spark was consistent, it is. I moved that plug to #4 and no CEL for #4. Havent moved wires around yet, but before the HG job I was getting #6 mis fire and replaced the wires and plugs and still got the #6 mis fire afterwards. I didn't use the wires that are suggested on this forum just went down to autozone and got the duralast cheapos....

I guess the next thing would be to make sure the wire is on the coil and swap it with another wire to rule that out.

 

What do you have for fault codes?

 

P306.