Hey everyone! I have an '06 3/4 ton Quadcab with a 5.7 Hemi with just over 100,000 mile. My check engine light came on and the code I got from my Hypertech programmer is P0420, any suggestions on whether I can fix it or take it to a shop. I'm also needing suggestions on improving the mileage, it's getting about 10 mpg now at 60 mph and less. Thanks for the help in advance!

 

welcome to dodge forums, i am sure u would enjoy a lot on this place

 

P0420 1/1 Catalytic Conv Eff

Its whining about cat efficiency. Means either your O2 sensors are going bad, or the cat is. Given that you are getting crappy gas mileage, I would start by replacing the pre-cat O2 sensor on the drivers side.

 

Welcome to DF!

 

Okay thanks for the advice.