P0420 Issue

[EvilSmirk]

Been having some problems with my Camaro as of late. Ended up with some substantial loss of power and the conclusion from the board was some bad fuel and/or something wrong with the coils, wires, or plugs...which makes sense to me. Replaced the plugs, they were probably just about do anyway. Ended up having to replace one of my ignition coils as well. The car ran good for about a day or two and now I'm throwing another code and still having substantial power loss. Took my Camaro to Advance Auto Parts yesterday and they scanned it for me...now she's throwing P0420. I've done a search, but what I found didn't really seem to help me out.

My car is a 3.8L 2000 Chevrolet Camaro with a Flowmaster exhaust, about 102k miles and the stock Cat. I live in VA, and while the cars are inspected, I'm not entirely sure about emission or visual checks. I'd really like to not have to take her to a dealer and have them charge me my first born to get the Cat replaced.

Can anybody on the board offer any reasonable alternatives? Will replacing the Cat get rid of the loss of power issue and bring her back to where I want her to be?

(Sorry for being a newb)

[98Camaro3.8]

Re: P0420 Issue

P0420 says the catalytic converter is not working the way it should. It could be a bad cat, or it could still be ignition related. Did the other 2 ignition coils test good? Did you change the plug wires when you changed the spark plugs? Did you maybe allow a plug wire to lay on an exhaust manifold and get burned after changing the plugs?

A misfire would allow raw fuel into the exhaust, which would cause the sensor to think the cat was not functioning correctly. Or it could overheat the cat and cause it to fail.

Since the previous problem was related to ignition, I would finish up checking the ignition system before looking at the cat. If that doesn't fix it, you can always buy a high-flow cat online for $60 and have a shop weld it on for another $50-100.

[EvilSmirk]

Re: P0420 Issue

I'll take a look at getting the rest of the ignition issues sorted out. I did a visual check of the coils this past weekend by unplugging the cables, taking out the fuel pump and ignition fuses and having my wife turn the key. Perhaps not the best way to check them but it was all I could think of. They all seemed to be firing consistently between the posts and in the correct order.

I did not replace the cables when I replaced the plugs unfortunately. Before going through that and the cost associated, how can I check to see if they are working properly? I've heard of using a spark plug tester, or something to that effect, but haven't used one before. My understanding is that you plug the tester into the spark plug side of the cable and attach one of the contacts to a chasis ground, have someone turn the key, and check for a spark. Is this correct? If I'm correct, I was thinking of checking to see if it's actually the cable or the coil by switching the cable with one that has shown to work and seeing if that fixes the problem, does that make sense?

In theory if it is still an ignition system problem...i.e. coil or cable, then taking care of that should eventually allow the misfires to cease and get the sensor some good exhaust to check correct?

Thank you for your input.

[97rs4life]

Re: P0420 Issue

po420 is a bad cat code. Replace your cat will fix your problems or gutting it.

hit your cat with a hammer once and listen for rattles, also does it have a rotten egg smell from the exhaust?

[EvilSmirk]

Re: P0420 Issue

I was talking with some other guys and since I'm still having the reduced power issue, hopefully caused by a random/multiple misfire like before, I'm going to replace the cables first and see if that handles the power issue. If, after getting the power issue resolved, I get the codes cleared and it comes back I'll explore replacing the Cat. Sound like a reasonable approach?

Liking the Avatar 97rslife!

[97rs4life]

Re: P0420 Issue

REPLACE YOUR CAT!!

a clogged cat will cause random/multiple misfires.....

REPLACE YOUR CAT :)