Hey guys. I just got my headers installed and decided to crank the car. I started it open headers and instantly I saw service engine soon flashing. So, I hooked up my scanner and got PO303 Cylinder 3 misfire. I did new plugs and new wires. I checked them. It's on the opti and on the plug good. I checked everything that I could think of. Also, I removed the A.I.R. system. Any ideas on what is causing the misfire will be appreciated. Thanks

 

Well, obviously there is a problem with cylinder 3. First, look over your spark plug wire routing again, and double check to make sure it is correct. If it is, then try swapping the plug from that cylinder with another and see if the cylinder misfiring changes.

 

Check plug & wire again. Check that boots sit tight on opti and plug. From a positive point of view - it is one of the easiest plugs to access

 

Cracked insulator on the plug? Plug not tight? Wire damaged during install? Did it run long enough to burn the wire?

 

Hey. thanks for the replies. I've switched the plug and the wire with pieces that were fine when I took them off. It still missfires either way. All I know for sure is that the driver side header is much hotter than the passenger side header. Any more suggestions?