So i changed the oil on my 01 XJ and before i did that, i added seafoam on the hose that goes from the engine to the master brake cilinder and once i took off the hose to add seafoam the check engine light went on. At first i thought it was from the hose but after i took it to check the light at autozone they told me it was the ignition coils multiple missfires cilinder 5 & 6...

Does it mean my coil rail is messed up and have to replace the whole rail again or could it be just the little boots?? Why did this happen after i removed the hose though?? Im confused??

Best to post the actual code numbers here, as with OBD, the devil is in the details.

If the check engine light is not "flashing" (is it?), then I'd recommend driving it for a while, a highway jaunt, to see if it works itself out.

Crap! Yea i forgot to ask for the code. The light stays on though. I drove it 40 miles today already and nothing...? Its driving fine though but im still concerned about it..

Removing the hose caused it to run lean. Probably the rear cylinders closest to the hose ran lean to the point of misfiring. It should not of damaged the coil.

The detected misfires are the result of removing that hose and introducing an intake vacuum leak. Reset the MIL and move on.

Azs code reader (person) seem to jump on the ignition side of things ie coil first. other things can and will cause missfire.

Hey man having an 01 also when i did the seafoam i freaked also but it is due to the fact u pulled the hose like everyone has stated and it would cause a misfire. if running good now disconnect your battery enjoy a cold beverage and hook back up itll reset the light if it comes back on then you know you will have to dig a little deeper.

Yea but i had done this twice already and never gave me a problem till the third time?? So then my coils and rail and everything are fine??

Did it happen to you the first time u did it??

nope I did it not long ago and it the light came on. the coil rail setup on ours isnt exactly like the old tried and true distributor cap ive got 138000 miles on my original one. thought about replacing it just to see what it would do then thought id rather have 100 bucks in my pocket. really though disconnect your battery to reset the light drive it if the light comes back on with the same code then we need to do some further digging.

Yea i guess ill do that to see what happens next. Hope it isnt the coil rail. I really dont wanna pay 100 bucks for the rail...

ponky to tell u the truth since you said its running fine now i can garuntee you rail is fine. if your rail was badit would be missing all the time.

True.. Sounds like common sence to me lol
Well if it keeps givin me problems atleast i know what it can be. Still thinking if i should seafoam it again in the future to let all the bad stuff out???

Ponky instead of seafoaming that sucker every month why dont you do a quick search on cleaning the IAC and throttle body that will do more then that seafoam. seafoam is good stuff but dont let it be a remedy to other problems. take your throttle body off search real quick on cleaning IAC and throttle body there are a million threads from all over explaining in detail how to do it very easy if you have a 10mm socket u can do this. this will benfit you most of all!

Yea seafoam is easy to use thats why i use it. This last time i did it hardly any smoke came out so it must hae been clean. I should clean the throttle body one day though since ive never done that to it.. Ill do some google and youtube searches see what i come up with.. Thanks for all the info man i gladly appreciate it!