The car started acting up a few days ago. It wouldn't start unless i gave it gas and then had to keep pressing the gas for 20 seconds or so until its able to maintain ~800rpm (rough idle tho) by itself. When i give it gas it would stagger and try to die around 2000 rpm, but would sound decent above 2500. However, the first time i brought it up to 5k, there was a pop and a cloud of black smoke. There was less smoke after that. There is also water and oil or unburnt fuel (black but thin) in the exhaust (on the tips). I was convinced it was the MAF (the smoke is a recent thing), changed it, but it didn't help. I'm waiting on a VAG cable to see what the codes are. Does anyone have any other ideas so far?
Also if i give it gas and rev it up to 6k, then let go off the gas, the car dies. If i keep it up as 1500, then let go off the gas it levels off and idles at 800.

A lot of people have said it is a clogged catalytic converter (and i do have a CEL for it). Im just waiting on my VAG to come to make sure its bank 2 and not bank 1. Meanwhile does anyone have any other ideas?
thanks

Also is there a point in buying a hi flow cat (Labree)? Will it pass inspection? Does it matter that one of them will be the OEM one and the other a high flow?

 

sounds like that car was running so rich you fouled your cats. if its backfiring or something when you rev it that high, perhapse you shouldnt do that. its very bad for the car. im guessing this is a 2.8 because you said you have more then 1 cat. do you have a CEL for a bad cat or you just have a CEL in general? you should find the actual problem before replacing things. you could also borrow/buy a pair of test pipes and see if that does anything, but i think theres an underlaying problem, if the cats are clogged, why are they clogged? what caused it? thats the question you need to answer first.

a labree cat will pass inspection in my state but its different in many places. if it were me i would replace both of them at the same time, but you could technically use one OEM and one hi flow. the oem doesnt have as much restriction as you would think, especially on stock power levels.

 

well the car has 150k miles on it and cats do have a definite life time. I got a code for a throttle valve controller malfunction today so im guessing thats why it staggers. However i don't see why that would cause unburnt fuel and smoke because the TB doesn't control mixture. Looked under the car and saw that the other cat (the one without the code) is an aftermarket one. Could o2 sensors be the ones making the car run rich?