I have a few engine codes... PO422- Main Catalyst Below threshold Bank#1. And PO313 missfire#3 cyl. Had these codes come on about 700 miles ago. Changed plugs and reset codes. Now today the came on again. also my turbo is bad, but will be replacing it with a slightly used one. Can anyone tell me what I can do to get rid of these codes?

 

swap your coilpack and see if the misfire follows it. i doubt it will because that would be too easy of a solution lol.

 

so if its not the coilpack, and for your sake Lefty i hope it is, but what else would cause those codes to throw? whats the damage? techs, got any input?

 

well the main catalyst code is probably due to the misfiring for 700 miles. ECT is another possibility too. usually the plug wires don't go bad on our cars but it's another possibility. excessive engine movement from bad mounts could contribute too. misfires are tricky problems, pm auditech79, he's the man

 

yeah the mounts on the car I think are bad. it tends to shake a bit when the gears are shifted. ECT? what is that? I checked that coil the last time and it had plenty of spark. But I will check it again.

 

ECT is the engine coolant temp sensor. There could be two problems here though - the misfire is likely to be either the coil (seems to be a known problem on the 1.8T), a plug, or a wire. The low threshold code could be a bad secondary oxygen sensor on the driver's side - the code definition could mean that the ECU thinks the catalyst is operating below the acceptable threshold of cleansing (which could be because of a bad secondary o2 sensor - its purpose is so the ECU can compare its readings to the primary (pre-cat) o2 sensor to judge the operating health of the cat). I agree with Hiwords - swap the coilpacks and see if the code moves to another cylinder. That'll tell you if the coil is bad. If so, you can replace it relatively inexpensively, delete the codes again, and see if the threshold code comes back. If so, you'll have to diagnose that separately, and I'd look at o2 sensors for that. Maybe you'll luck out though and fixing one problem will clear the other as well.

 

but how come it went 700 or so miles without it comming on?

 

Could just be a gradual degradation that only recently got bad enough to trip the CEL.

 

because you have a cat that is going bad

 

could that be because of the bad turbo? exhaust has light smoke with hits if oil smell.