some background info: ever since i put the pacesetters on, my truck misfires ONLY when it rains. the only logical explanation i could come up with was that the stock spark plug boots were touching the header pipe, and it would cause a short when it gets wet. i bought some multiangle msd wires and put em in, now none of the boots are in contact with the header. yesterday it rained. yesterday it misfired

i dont know what else it could be, it only misfires when it rains...thats not just a coincidence...and it only started happening after the headers went on

any input is appreciated

thnx in advance

 

Did you install the headers with the spark plugs installed in the heads? The reason I ask is you could have possibly bumped one of the plugs during the install and cracked the porcelan on a plug. I have seen even a slight crack cause a misfire, it doesnt take much at all sometimes. That's why if I am ever installing plugs on something and I accidently drop a plug on the concrete I will automatically throw that new plug away and get another one. I have seen it happen a number of times. Just something to think about.

 

yup you bet.. check your plugs

 

thanks i never thought of that, i'll look into it...but would the crack make it misfire consistently or only when it rains like mine does??

 

Rain wouldn't really be getting up in your engine bay too much. You probably have a leak at the header collectors and it's screwing with the o2 sensors somehow.

 

oh ok, thanks man

 

It is possible. I have been working on engines for about 14 years and I have seen some ignition components do some weird ****. Not saying for sure that a plug is your problem but I do know personally that's where I would start.

 

It's not necessarily a cracked plug. It's more likely carbon tracking. If you had the plug wires touching the headers for a while, and you had spark jumping thru the plug wire end to the header, it leaves carbon tracking on the spark plug porcelain. You may or may not be able to see it. It will still misfire until you replace the plugs also. If you wait too long, and the spark is jumping thru the plug wire end, it will damage them also.

 

alright i'm gonna get some new plugs, nothing to lose huh...thanks i really appreciate it

 

yea the damn wires were toughing the headers for almost a year :/

and when i took off the stock wires to replace em with msd ones the other day, one of the wires was really fucked up...it got cooked with all the heat :/

but i am gonna replace the plugs asap, i really hope thats it...

thnx everyone