2000 Accord bogs out and dies with P0420 code
 

Hello all.. i have been driving my 2000 Accord 4 cyl, auto trans, with 160k, about 175 miles a day for about a month. No problems at all!!

Other day it just dies while cruising at 75mph, I put in neutral and starts right back up and keeps going. Next day doesn't happen, but the following it does. It kind of feels like bad gas, throttle is not responsive.

Then the P4020 code appears, and car really starts running like crap! Take to the dealership and after a long discussion with a tech, need to change the CAT.

So swing to auto zone pick one up(don't forget the gasket like i did) and put it on. Take cable off reset ECU, Quick easy no problem.

Now the problem! Running worse and code came back on! (The CAT needed changed it was all broken up!)
PLEASE HELP !!!!

Suggest pulling and cleaning spark plugs. They may have fouled due to excess back pressure.

Also check wires by spraying w/ fine mist of water at night. Any sparks jumping or severe missing mean bad wires or distributor cap.

regards

if you ever get a bad cat code and you want to buy some more time you can do the spark plug anti fouler mod and that should turn the code off. just google it theres a bunch of articles

with his car randomly shutting off while driving could it also be his ignition switch?

Yes... Can you make it happen by wiggling the key? (just don't be stupid in heavy traffic)