I have had this problem with both of my 92 Camaros at 110 MPH they back off. I have heard about bypassing the VSS, the problem is i still want to know how fast im going, and will this screw with my computer since i am running a speed density system. I would like to install aftermarket speedo and controller without compromising performance or my car running at all. Has anyone tried this and did it work.

 

Pretty sure the ECM puts a hold on top a WOT so changing speedo won't fix that. I think you need a chip that eliminates that as heard it was a common issue limiting true top end speed. If you are running the 110 speedo get the 140mph one as that is what I did with 91 5 speed car as I added a 350 with carb.

 

What exactly is it doing?

Might check out this article https://www.thirdgen.org/unlimited I'm unsure how it would affect the TPI.

I know my Formula 350 doesn't have a speed limiter.
It's been up to around 130+ MPH on the dyno in 3rd gear.