CEL P0420 and P0430 thoughts/questions

2006 4.0 V6 with a little under 90k

Both P0420 and P0430 CEL popping up consistently.

Trying to do the cheap things first (before 02 sensors or cat replacement)

- Cleaned MAF with MAF cleaner

- Ran Seafoam through engine, fuel tank, and main vacuum before oil change

- Cleaned air Filter

- Replaced spark plugs

STILL HAVE CEL LIGHTS

- Need to check for exhaust leak still

- need to run truck at night to see if cats or manifold is glowing red after running truck.

- I heard putting a gallon of lacquer thinner in a half full (see, I'm an optimist) fuel tank and running truck at 2500 rpm's for 30 minutes + or - will clean out most dirty Cats. Would this cause other problems?

- Maybe drill hole in exhaust before and after cats and checking pressure differences


What do you all think?

 

I would not put lacquer thinner it may eat all the plastic vacuum tubing.
Here is what I would try. Fill up with High Octane Shell gas, take a trip to that has 200 miles one way with transmission set on 4 instead of D.
Shell high octane has best cleaners there are and high octane fuel is good cleaner in itself. If you can wrap your cats with heat shield wrap (Autozone sells them)

 

Hmmmm, good idea. (heat wrap on cats)

 

I'm had the same issue... except for the CEL P0430... after cleaning both my A/F and O2 sensors in SeaFoam I've been good to go. Plus, I stopped getting gas at Kroger and started tracking the Ethanol amount in the places I go.

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