99.5 jetta 2.0 AEG Engine Codes, Please help

Hi, I'm new here looking for help with some error codes on my 99.5 2.0 AEG jetta 99,500 miles. I am not seeing a check engine light for any of these codes, the light stopped after replacing the MAF and clearing them.

Currently I am getting both p1128 (too lean) and a p0172 (too rich) codes. They randomly occur after I clear them with a code reader. Once I got the p0422 caltalytic also and plan on getting that replaced under extended warranty when it repeats (TSB says so). Last week the dealer replaced the pre cat o2 sensor and updated software under recall, and I installed a new (reanufactured) MAF sensor, cleaned all the screens and filters in the intake, checked for intake leaks.

The more I drive the vehicle the louder it seems to sound/resonate under harder acceleration and higher rpm but runs smoothly. The catalytic is clearly rattling and some backfiring sound inside of it, heat shield seems fine. It sounds like there may be an external leak, but I can't find any.

When cold it has a slight hesitation for the first minute like a misfire then takes off no problem for the rest of the drive.

My goal is to get the other codes to stay clear and wait for the 422. Are these all related in some way? What else can I check? Please help and thanks.

Duane

Duane,
you have codes Now?
all the code you have stated all in some way or the same you front Ho2s was you lean and rich fault unless it is still coming back?
as for the catalyst if it is rattling you extended warranty should not need to see a code as the catalyst has failed. it is making noise and rattles it could cause larger problems to the motor if it keeps going.

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Volkshaus,
I cleared the codes this morning after noticing the crankcase blower hose to the air cleaner had fallen off. So far no codes but it may be too early to tell. This is upstream of the MAF, so I am not sure if it appears as a "vacuum leak" that woud trip the MAF codes, but if anyone knows better I appreciate it. I'll check regularly.

Is it possible for OBD-2 to store codes like p1128 with no check engine light? That seems to be what happens here occasionally. I don't think the light is burned out since it worked last week, maybe a coincidence though.

I just called the dealer and they said they need to have p0422 come up for catalytic warranty repair and all other codes need to be cleared by fixing the problems. I read that in a TSB but can't find the link again. I'll have to wait and see and live with the rattling I guess.

Thanks for replying.

Duane