Just the other day I installed Pacesetter Headers on my 2000 GTP, as well as a 160 T-Stat and new Autolight XP Iridum plugs. Since then she runs like hell. No power whatsoever when you give her gas, sputters and is missfiring terribly. plugs are gapped at .70 as this is where they were out of the box. I dont know what else it could be. Ive checked all the vac lines and MAF sensor and those are all good. Do headers really make that much of a difference that i need a tune or is something else going on???? Any suggestions??
Thanks