Quote Originally Posted by zhpnsnv View Post
Interesting thread. Back when I first owned my car it had a pretty significant dip, so I had the dealership send the ECU out and do that fix. It helped a little, but it was still there.

I sold the car and the following was done: Dr. Vanos, GAS DISA, and a custom ECU tune (also perf muffler). The dip is completely gone in basically all circumstances. The only time I felt it a little was at 1/2 throttle, 4th gear pull one time. Not sure what the custom tune did or if it turned off the DISA altogether. All I know is it pulls beautifully, way better than when I sold it. It's weird -- I accelerate in first and second totally expecting it to be there because that's what I'm used to, so it's odd now that it's gone.
I never had the dip for the first 5 years of ownership. In the last year I've noticed it badly in 2nd gear and it hurts my soul lurching forward and then back into my seat with my foot to the floor whenever I push through 4k rpms. Never had the issue before and all of a sudden here it is.

I have rebuilt my DISA valve with the GAS kit years ago. I have a vacuum leak somewhere, need to find it and solve that (no light but rpms dip down when idle and bounce back up slightly). I also have a shark injector I need to install. The shark claims it fixes the 4k dip, but from the other posts in this thread it doesn't seem to work for everyone.