Found the issue cat delete was making 02 sensor throw a code. Time to put the cat back on :P

Thanks again guys

 

that wont fix your problem

 

That won't do anything, the only thing the rear 02 is good for is to make sure the cat is working. Just out a couple anti-foulers on it and the code will go away. Definitely not your problem though

 

Hey guys, I'm having the same problem. This particular issue with my 2001.5 A4 1.8t quattro tiptronocs bone stock....well, I did install a boost guage though! So, this has been going on for over 2 years and I haven't gotten to it sooner because there have been other issues with the car I've been fixing and hoping it would have fixed this issue....no luck! Two weeks ago I installed the boost gauge and finally last week the no power with boost occued, so to get the car to accelerate I pushed the peddle to the floor & this time the CEL came on. The CEL has never come on before but that evening I went out to get dinner, last Friday I believe & the CEL went out. On Wednesday of this week I borrowed a coworkers obd2 scanner & the it threw a code of P0136 O2 circuit (bank1, sensor2) & I then cleared the code. I've driven the car most of this week and it only did it again yesterday w/o any CEL this time. As I've read on other post including this one the consensus is that the after cat o2 sensor will not cause this issue...
•coolant temperature sensor is original as far as I know
•cleaned maf, intake manifold sensor, throttle body just over 1 year ago (was hopping it would get rid of the CEL) Note: 3 days after cleaning those components I drove to work and CEL was off, then went to get lunch and engine would barely start and ran very rough while the CEL was flashing ( had a car towed home and it sat for one year)
• One year later I replace the spark plugs, will probably double check the gaps, anybody tell me what they should be? the misfires ended up being bad coil packs on cylinders 2 & 4 so I bought 2 coil packs from autoze. Then soon after had them all replaced at a dealer due to a California recall (so now I have to lightly used oil packs)
•Has a k&n air filter

there is one other part I replaced not sure its exact part name, I will find out and post back.
I really hope we can figure this issue out, and a Big Thank You to everybody who has and is helping!