Hi, im new to the DF. I have a 2nd gen 99 ram 1500 with a 5.2. Im down a quart of oil about every 5-7 days. The p0420 code, first bank is on. Theres no apparent oil leaks other then a lil drip from the oil pan gasket. Whenever I come to a hill, especially in a higher gear, my motor sounds like a can of spray paint being shaken up. The motor has high mileage on original motor (212,000). I dont know if I should start by replacing the plenum gasket or catalytic converter. Please help, any advice is GREATLY APPRECIATED...

 

You should start by replacing BOTH along with the front O2 sensor which is now toast as well. If money is a problem, replace the plenum gasket with the aluminum plate version and cut out the catalytic converter and put a piece of pipe in its place until you can afford to replace the cat too. It's also probably time for a good tune-up since a horribly blown plenum will start fowling plugs. Looks like it's time to put some pretty serious time and repair money into this truck if you plan on keeping it...

 

I would start by taking your air filter out and looking down the throttle body with a flash light. If there is oil in there then your plenum gasket is blown. What happens is that oil gets into the air that's going down into your cylinders (where it burns, then exits as exhaust), on it's way out, it clogs up the catalytic converter and fouls up the front )2 sensor. If your burning 1 quart of oil a week and you only have a little oil drip, I'd bet that your plenum is blown. Fix that first, and then quickly replace your catalytic converter and front O2 sensor.

 

Thanks for all the advice. I didnt know replacing the cat with a strait pc of pipe would be okay. Thats definitely gonna help. Im not the greatest welder, do they sell some sort of coupling or sleeve that would make that job do able without welding?

 

Yep i know autozone by me carries coupler. all u need is a hacksaw or die grinder to cut to length

 

Be aware that removing your cat is against the law and you wont pass inspection if you have them. People do it all the time, but just be aware of the consequences.

 

Also, I think the 99 still uses the two in, one out cat. Putting a coupler on that will be problematic.

 

I'm only suggesting cutting the cat out as a temporary solution if funds aren't available for both repairs...the trucks were designed to operate with a fully functional cat...be aware that removing it will trigger O2 sensor codes (downstream) unless the "non-fouler" trick is used.

 

lot of good info here love this forum

 

Yeah, I know you meant temporary, but wanted the OP to know that too