Main Catalyst below threashold Bank 1 ???

[sirmagic]

Good day all.
Using the Global OBDII DTC codes I now know why my "Check Engine" light is on.

The Car history : 2000 Accent GL, 5 speed @ 93k miles.
I've replaced my spark plug wires at 60k and plugs again at about 75k
In August both my Crankshaft position Sensor and Mass Airflow Sensors were replaced.

I have the following error codes.

P0300
Random /Multple Cylinder Misfire Detected.

P0301
Cylinder 1
Misfire Detected


P0422
Main Catalyst below threshold
Bank 1

P0301
Cylinder 1
Misfire Detected


So here's the obvious question what are these codes trying to tell me ?
I've noticed a drop off in power and gas milage.
Then of course the suggested fix before I go blindly into the dealer.

Magic

[Edited by sirmagic on Dec 4, 2005 1:29 PM]

[J.P.]

Random chance, but those are exactly the codes I got when my EGR valve was seized in the partially open position ('01 Mazda Protege, not my Accent). I had been chasing ignition problems, but down at the bottom of the troubleshooting list was EGR flow. That's what it turned out to be.

Just a thought,
- JP.8D

[DIRTYsouthBB6]

You did good by reading the codes, but it's hard to say what is causing them without testing individual components or troubleshooting.

You might try testing the voltage on the oxygen sensors and checking the gaps on the spark plugs. You also might want to inspect the coloring of the spark plugs and find a shop with an emissions dyno to check out what air-to-fuel ratio your car is operating at.

[sirmagic]

Well I'll check out both your suggestions Gentlemen. As for the O2 sensors, I had the problem of Catalyst below threashold Bank 1 before I replaced BOTH O2 sensors and it didn't go away. It just dawned on me I should have mentioned that before. I'll check the gap on my plugs as well. Now when I replaced my plugs and spark plug wires a while back the check engine light did go off for about a week, but it came back.

I'll try your suggestions but I'm also still taking them folks this is driving me nuts.


Magic

[gmc2313]

i had the same prob p0422, had to put a converter on mine( 700$)