engine codes what the....

Okay.... You have 3 coil packs on a rail and are getting only one code you can assume that it is not an electrical or coil problem as cylinder 1 and 6 fire off the same coil pack.

Did you blank the code with a tool or by disconnecting the battery?

Did you save the old plug?

What did it look like?

Was it unusually clean compared to the others?

Was it carboned or oily?

What does the exhaust look and smell like?

Is this a recent or existing problem?

Did it happen all at once?

What, if anything, did you do when or shortly before the problem started?

How many miles?

What kind are the new plugs?

Have you cleaned the throttle body?

Did you use an upper engine/ valve carbon cleaner (SeaFoam, etc?)

Yes the plug was more dirty then the rest. the jeep has about 67,000 miles on it. See I was thinking for sure it was the coil, but that makes sense thats its not. I replaced it with stock plugs. I think they are autolites. There was one article I read said I should run champion truck plugs. The plug I took out wasn't oily or yellow it was just really black.

Is there a chance that I could have a bad cylinder. like low compression, a bad valve or something. thanks for all the help so far any more info would be great....

What about the other questions? While some might sound silly they were asked for a valid diagnostic reason.

For example the question "What does the exhaust smell like?".... if you said it smells 'sweet' that might indicate you are burning antifreeze....

What we now know is you have an '01 4 liter with 67k, may have new standard Autolite plugs and the old plug was some form of black.

Do I understand that it backfires also? How often?

Oily (wet) black or dry (carbon) black?

PS: Please use quotes, other will jump in with ideas if they know how the diagnosis is proceeding...

So her are a few more ansewers to the questions:

spark plugs dry black / they are champion brand.(new and old)

exhaust the exhaust dosen't smell sweet it smells a little rich We used a computer to pull the code the first time and we also earsed it. today I earesed it by just un pluging the battery.

THe engine light has been on for about 2 to 3 months, but I didn't worry about it it was running good. then all of sudden the light started to flash why I was drivinh it and started to back fire. It seems to idel ok but the bottom end wand why your on the gas, is sluggish and back fires and spits. but full trottle it seams to run ok.

THanks for all the help you rule.let me know if there is anything else you can think of.

Take a real close look at the spark rail and check for melty spots. Some of them develop arcs internally and that causes all sorts of problems.

i think that i got the boot on correctly I have taken it ogg again and put it on to make sure of that. Can you buy just new plug boots or do you have to by a whole new spark rail.

Also dose anyone know what the compression should be I'm going to check that out tomorrow. I would just like to thank everyone for all the help. It's been great. I was really hoping that someone out there has had this problem and knew just what it was...