p0420 and p0430

[droppedoffroad]

Just had to replace intake manifold gasket due to a leak and also replaced dizzy with a billet one. everything thing was fine seem to run good but now throwing codes 0420 & 0430.

What are my first places to look everything that was unplugged is plugged back in oil pressure reads fine coolant temp reads fine fine like it has

Truck is a 98 Silverado c1500 with 5.7 vortec

 

[Steve's Chevy]

It wants to be lifted, that will fix everything!


Yep!

 

[1997chevydriver]

Check all grounds and fuses.....

 

[droppedoffroad]

That's only cause you want my rims and tires lol

driver, I've checked fuses and grounds an took it to Chevy yesterday.... According to them my cats are toast being as they are factory and have over 200k miles on them. I just wanna make sure it's not something more serve and want people input on it.

Im thinking about building a ground kit to ground the truck more.worth it? Or is our trucks pretty well grounded?

 

[twomanymontes]

Check to be sure the downstream O2 sensor are plugged in.

Do you have a scan tool? Monitor the front and rear sensors. Once the engine is at operating temp, hold the throttle at about 2500 RPM. The fronts should be consistently switching over and under .450 volts. The rear should be staying around the .400 to .500. If they rear sensor is reading the same as the front, the cats are bad.

Hope this helps

 

[Steve's Chevy]

Edit ..... Delete!

 

[Steve's Chevy]

That's only cause you want my rims and tires lol

Ya that's it , you got me!