About 2 years ago, I had the dealer replace the bank 1/rear cat because of a P0420 code. This was at 79,950 miles. Yes, 50 miles prior to the emissions warranty expiration!
About 6 months ago, at 90,000 miles, I had the CEL come on and it was a P0430 code, bank 2/front cat. I changed the plugs and wires and cleared the code. The code did not come back until recently.
When I was driving to PA last week, the CEL came on and I had the codes scanned when I arrived. The code was a P1151, o2 sensor lean/no switch (bank 2/front). I replaced that O2 sensor last night, cleared the codes, and went for a test-drive to see if the problem was fixed.
When I got home, I rescanned the codes and got a pending P0430 code. I went for another test drive and the pending code became a hard code, turning the CEL on. I cleared the code, and drove back home.
Tonight, coming home, the CEL came back on, P0430 again.
I did a little research on this forum and found that Big Jim said that he had gotten these codes intermittently, but they went away, and he thought some reasons why is that he cleaned the throttle body/intake/combustion chambers on a regular basis and kept the ignition system in good shape.(This is one reason why I thought to change the plugs/wires when I got the P0430 the first time).
I had never really cleaned the throttle body/intake/combustion chambers on this Contour, so I decided that would be a good start.
I took off the air duct, and started the engine. It died right after starting. My old '95 Contour had no problem starting when the air duct was off. I thought maybe the MAF should be unplugged. I unplugged it and it started right up without dying.
Then I got a can of B12 Chemtool Carb and Choke Cleaner and sprayed it in while revving the engine up. I probably used about half a can. It made the exhaust STINK. I am sure some of it was going through the engine unburned. I made sure the secondaries opened up a few times while I was spraying it in. I didn't spray it all in at once, I sprayed on-and-off for a few seconds each time, to avoid overheating the cats.
After I was done I cleared the codes (P0430 and a code from the MAF being unplugged), and went for a test drive.
When I got home rescanned the codes.
"ALL READYNESS TESTS COMPLETE", said the scantool. Then, without displaying any codes, it went to menu. (If there are any codes, pending or hard, it displays them after it says whether the readyness tests are complete)
Could it be? It completed all readyness tests without detecting a problem with the cat? I double checked and went to the data->codes->pending display, and it said "NO CODES AVAILABLE".
I guess I'll find out in the next few days if the cat still has problems, but this is really encouraging. I wonder what effect the B12 Chemtool had on the cat that made it start working better?
