jbenns45

hi all

so ive had this 2002 a4 for a few months.
when you push the gas all the way down the RPM's climb very slowly and it gets really loud. you can hear the turbo spinning up but it doesn't pull like it's supposed to. It actually accelerates faster when you push the pedal less than halfway.

it's at 120k


i've replaced:

fuel pump
fuel filter
DV
n75
spark plugs
trans fluid
oil pickup screen
oil pump
timing belt
water pump

i have cleaned:

IAT sensor
MAP sensor
throttle body
MAF sensor

the wastegate actuator is fine and works as it should, i have done the n249 bypass.

i am leaning towards a clogged/bad cat, or possibly MAF?

scanned with vag com, no codes, pressure tested holds 15 psi

I AM COMPLETELY LOST AS TO WHAT IS WRONG>>>
PLEASE HELP

thanks
-Josh

lyleswk

Did it drive okay when you first got it before any work?

need_corrado

Stock exhaust?

Sounds weird, but I had an issue like that and tried everything and spent hours online looking for a solution.
Brought it to my mechanic and turns out the Catalytic Converter was clogged and needed replacing. I replaced it with a free flow test pipe and problem solved. Check it out.

jbenns45

i was considering the cat, i tried running without the top o2 sensor in and didn't notice any difference (apart from the noise lol) so now i'm not so sure.....i did put a boost gauge in since then and boost appears ok? around 8 psi and its a stock AMB engine.

and i bought it with this problem....

what do you think about the cat?

thanks
-josh

lyleswk

So, before you go rip anything else out, when you say you floor it, what gear / rpm / speed / etc etc?

jbenns45

sorry for the late reply i have been busy lately.

when i say i floor it I mean from like 5mph to 45 mph with the pedal all the way to the floor. It gets really loud and the rpms slowly climb and it slowly accelerates. Then at around 4000 rpms it jolts (almost like a rough transmission shift but its in the same gear) the car accelerates much faster and it quiets down.

im leaning towards a bad throttle body maybe? do those typically fail at 120k miles?

otherwise could the IAT or CTS sensors have anything to do with it?

thanks
-Josh

lyleswk

Your last description makes it sound more like transmission. What tranny do you that?