Chevrolet Repair: Auto Repair, p0420 code, catalytic converter

Question
Hey Wayne, I had to ask a new question because it wouldn't let me follow up anymore. So I should take it back to the person who did the intake gasket because if they didn't use the torch wrench they are at fault for the new damage which they should fix for free for not doing it right the first tie. Correct? Also you didn't give me a reply to the P0420 code. I don't know if you have any suggestion or not but let me know if you do or not. About the misfiring, the plugs and wires are brand new from the dealer and its still misfiring so it's probably the ignition coils. Correct?

Answer
HEy,

The P0420 is because of the missfire.  Its a catalytic converter efficiency indicator.  If the cat is full of HydroCarbons the secondary 02 sensor will flag the converter as inefficient.
If you have spark at the holes that is missing that doesnt necessarily mean that you are getting combustion.  I would really suggest having the rocker bolts checked.  You might want to go to another shop to have this done though.  If they can't be helicoiled and the heads have to come of there isnt a chance in hell a shop is going to do that for free if he can't think up another excuse for it.  Wanna see some pictures of what happens?  We did one this week for the same problem.  email me at waynehowie@rogers.com

w