I have a 2004 STI and we changed the sparkplugs yesterday. After the change we drove it and it was hesitating really badly around full boost. The CEL blinked and came on and it showed that cylinder 1 was misfiring. We switched the coilpacks on 1 and 2 and it was still the same. Then i reset the code and took it for another drive but this time it was cylinder 3. I think all the coilpacks are fine. Any ideas?

 

Did you get the right plugs and also check to make sure they are gapped properly?

 

Yeah plug gapping and proper plus was my first thought.

 

+1 for gapping. feeler gauges saved me PITA.

 

I bought the NGK Iridium plugs, the guy said they were pre-gapped, but I'll check them to make sure. Any idea what they should be gapped to?

 

take a look in your service manual or look on here. but ya take a look at proper gap and buy a set of feeler gauges. pretty handy in many uses. (valve setting, piston ring gap check, etc. they cheap too. take a look and gap as needed. careful not to break ground, although u really gotta be mad at it to break it. LOL. GL!

 

That was it! Thanks guys

 

!

 

Good to hear.