Well guys and gals, I did an advanced search option and sat here for an hour. Im having nasty rev hang. As well as my old bmw 323is you get the typical flywheel answer. I dont believe this is the issue, because it just started acting up. Temps here are consistent, my driving (as far as i can tell) is consistent, and many other factors. I havent seen an official rev hang thread so I figured I would start this (correct me if im wrong please). Any one have any opinions on this issue besides the flywheel being dual mass? Vacuum line? Throttle cable? I would like to see some answers !

 

After doing a google search on some other audi models, I've come to some interesting points. Collapsing turbo hose, and a dirty MAF. I do have a K&N cone filter and it does not look the cleanest. The fix for the collapsing hose is taking a metal exhaust pipe piece and dropping it into the hose itself (rests against a ledge and will not fall further in) and cleaning/replacing MAF. Any other ideas?

 

Is the issue during WOT or when shifting gears?


The hanging RPM when shifting gears is caused by the dual mass flywheel, this happens because when you release the clutch part of the flywheel actually increases in speed to catch up with the rest of the flywheel. After it has fully unwound the flywheel then starts to slow down. This issue is fixed by going to a single mass flywheel with a sprung disk.


If you have a turbo inlet hose that is in fact collapsing, the best fix is to just replace it with a much stronger silicon inlet hose.

 

It happens in both cases, mainly just shifting. However when im on the highway and give it some giddy up and go, when i let off the gas its almost like a jerk forward. When I read about the turbo inlet hose collapsing they quoted " when you let off the accelerator it will feel like hitting a brick wall ". Thanks for the opinion mike. I think Im going to order a new silicone inlet hose. As for the flywheel, I might have to get used to it, a new clutch was installed before i got the car so its sort of back tracking to rip it apart and replace

 

The only way the inlet hose would cause that issue when lifting off the throttle is if the BPV outlet was being restricted and causing compressor surge at the turbo outlet.