passat 02, error code p0420, problems
 

New to the forum. I own a 2002 passat 1.8L turbo(not diesel) with 122,000 miles. I hope someone here can help me out. I had an CEL come on last week while driving on the interstate and my car began to shake and lose power. Went to the dealer and they said my coils were bad and so I had them fix it. I drove it out of the garage and 5 miles later the light came back on. I took it back and suddenly my catalytic converter was bad. Although the car drove fine with no obvious loss of performance. So I took it to an autoparts store and plugged it in to a diagnosis computer. I got code p0420 which is a "front bank" exhaust problem sort of thing. Basically the autoparts guy told me it is a front oxygen sensor problem, not the cat. The cat doesn't rattle when I drive or tap on it. So anyone, have any input here? And shoud I still replace the cat or just the oxygen sensor? Should I buy OEM parts, universal parts, or is there aftermarket parts that will improve performance? Thanks, Dacoontz.

Get a Bosch O2 sensor (the one before the cat).