After finally getting my 89 Corvette put back together after camshaft & other changes, I have a couple issues.

1) First issue is the speedometer isn’t reading the speed, it lights up but only says “0” & never changes. It worked before when she was parked almost a decade ago so I was a little surprised she didn’t. Checking codes I’m getting a 24 for VSS but I cannot find a VSS. I did find one guy on eBay selling one that seems to be form a later model 91+ that may work. Am I going in the right direction to repair this & is this my only option for replacing a VSS?

2) When she’s warned up & I push in the clutch coming to a stop she dies. I looked for vacuum leaks but didn’t find anything looking around. I was thinking it was likely the IAC at the bottom of the throttle body but looking around for answers I also ran across a process to set minimum idle speed. However does this need to be done after repairs or certain changes like I’ve done? Should I do this & if so do it after the IAC is changed or should I do that now before changing the IAC? Lastly how do you get the IAC off? I don’t have any tools that can get at it & it looks like the throttle body needs to come off. I have a new IAC in hand if needed. Thanks!



The spacing is too tight in these spots to get at the IAC


While the car wasn’t moving in this pic, that’s what the speedometer is looking like lit up.

 

Is your '89 an M6 or an A4?

 

Sorry, it’s the ZF 6 speed manual transmission.

 

You should have no issue with a ZF VSS for your car. Do the diagnostics but a buy shouldn't be difficult.

A GM# 10456089 or it's equivalent would work. There's not as many choices as there were but it should be doable!

 

Yep