No accelleration before 3k

[mattdev]

Ok, I got myself a problem:

Long freeway drive (about 4 hours). On the freeway, whenever I let it go under 3k the car doesn't accellerate. It just starts bucking until I downshift and get above 3k. It is worse at a stop sign, presumably so. I have to practically launch the car (rev up to 3k and ease the clutch and gas it) just to get it moving. It WILL NOT accellerate at anything below 3k. From a stop it seems to misfire and backfire, but rpm's will not increase at all (if under 3k). It helps if I give it more gas and it seems to accelerate only when the turbo spools.

I'm pretty sure it has something to do w/ boost, it bucks because it seems to instantly build boost. I have a few things to warn you about that are "wrong" with my car:

2.5" o2 housing, stock exhaust (long story, don't ask)
almost non-existent clutch

Could it be that the larger diameter o2 housing allows more flow from the turbo, but the downpipe restricts it... thus...I don't have a clue! Thats why I'm asking!!

Thank you so much!

 

[vr4gasmtt]

I'd take a look at your clutch, maybe your clutch is slipping making you have to rev more to get the car moving. My car does the same thing, but the clutch isn't as bad yet.

 

[poonman]

To me it sounds like your Mass airflow sensor, one time i was cleaning my car and soap and water got on my MAFS and it did the SAME exact thing, trying unpluggin it and see wut it does

 

[PieEyedPiper]

I don't believe this problem is related to your funky exhaust situation ( btw I have the same thing going on with the exhaust ).
Have you done a boost leak test?
Have you checked your spark plugs for correct gap or if they are fouled?