I have a 05 Pac... Please give me some insight on P0420 code( autozone readout) per check engine light...details below per autozone printout

Definition
Catalyst efficiency low bank 1

Proable cause

1.. Catalytic converter defective( failure possibly due to #2,3, or 4)

2... Engine misfire or running condition

3... large vacuum leak

4... engine oil leakage into exhaust - valve guide seals, pistonrings

now since I haven't had a tune up since buying the Pac 2yrs ago( dashboard reads 75,000 mi) , if I where to replace the the spark plugs could that correct the issue?

any insight would be helpful

Thanks

 

It might be a good idea to replace the plugs. Take a good look at the old ones as they come out. Look for indications of oil fouling (problem 4) or excessive heat damage (Problem 3). If such problems are found, you'll have to hunt down the cause(s).

Good luck.

 

thanks DCotter0579, also is there any good diagrams that show how to preform the tune up as I see there are many bolts / screws and plugs that appear that have to be removed

 

u have a bad converter a tune up wont fix anything plus they are 100k plugs

 

I agree, the plugs are good for 100K. It will not fix your issue. You need to have the emissions system looked at. O2 sensors, EGR,etc, but you likely have a cat converter going bad. They don't last forever.