random misfire after header install
Thread Starter
Teching In
Joined: Aug 2011
Posts: 13
Likes: 0
From: jacksonville, NC
random misfire after header install ok guys i just installed bbk LT's and ORY removed the pesky AIR and EGR, also new ngk tr55's and msd wires, and bosch 13111 o2 sensors. got it all done finally and it sounds nasty i love it. but the car runs rough and im throwing a p0300 random multiple misfire code. all plugs and wires are on good but the engine sounds like its running really crappy. i have very weak pick up until about 2500-3000 rpms then it feels good again. im waiting on a proper EGR plug and was wondering if maybe the piece of metal and rtv silicone that i have plugging it now may be the issue. can the seal being broken cause misfires like that. any help appreciated guys.
On The Tree
Joined: Jan 2012
Posts: 182
Likes: 0
From: Boston
get a 1 and 3/8" expandable rubber drain plug from any autoparts store to plug the hole (see below)
Also, I had the same thing happen. I had my plugs installed in the heads while hanging my headers. Well...after chasing down a backfire / missfire it turned out to be a plug. I smacked the header off the ceramic portion of one plug (cylinder 7) and cracked the insulating ceramic...That was the problem. (see picture below)
Also, I had the same thing happen. I had my plugs installed in the heads while hanging my headers. Well...after chasing down a backfire / missfire it turned out to be a plug. I smacked the header off the ceramic portion of one plug (cylinder 7) and cracked the insulating ceramic...That was the problem. (see picture below)
Thread Starter
Teching In
Joined: Aug 2011
Posts: 13
Likes: 0
From: jacksonville, NC
im really hoping that its not the plugs i also had the 7 and 8 in when i put on the hangers i installed them from underneath to try to save myself some time and effort for after i put the headers on bc 8 is really hard to get to. i guess if that ends up being the case after get the egr plugged then ill have to look into it. but wouldnt just one throw a cylinder specific code e.g. 0307 or 0308
Thread Starter
Teching In
Joined: Aug 2011
Posts: 13
Likes: 0
From: jacksonville, NC
thanks for the advice guys ill pull out the 7 and then 8 to see if either are broken but if it was just one wouldnt it throw a specific code? itll have to wait untill next weekend though i pulled my pcm today to mail it to frost for the tune. if the plugs are good i guess ill find a shop with a tech 2 that wont charge half my arm to use
