Yesterday I'd started her up (like normal), took her out of the garage and went on my way when I'd looked down at the cluster and it says 50mph when I'm doing less than 30mph . After noticing that, I'd made a U turn and headed home and shut her off. Let it sit for about 30 or so minutes and started it back up again, back out of the driveway and put it in 1st so I can go back into the garage so I can check on the mph reading. It's saying I'm doing 30 when I'm actually doing less than 5mph, what's going on?
After messing around under the hood (touching wires, tighting sensors, etc) and started it back up, took her around the block and it was normal. What could cause this? Is there anything I can do to prevent this from happening again? HELP???

 

Is your speedometer showing kmph instead of mph??

 

30 mph = 50 kph.

 

That's what I'd thought too but I'd looked at the speedometer and it's on MPH, I did click it back and forth just to make sure my eyes weren't playing tricks on me.

 

Do you have a speed compensator on? Yellow Box? Yellow Jacket?
Maybe your clutster is having a brain fart and is converting over to KPH but not changing the actual designation.

 

Nope, no yellow box. If it does have a "brain fart" then what can I do to prevent this?

 

Don't panic just yet. See if it does it consistently and also see if the odometer is affected. Really depends on what is causing this. Trace the wiring from the speed sensor on the side of the tranny as far as you can. There might be a break or pinch along the way. The speed signal goes in and out of the ECU, so check all the connectors there to ensure they're all solid. Could be a bad instrument cluster, too.

 

This wasn't the first time it did that, same thing happened when I'd first took the S out from storing it due to winter but I'll surely do what you'd recommended.

 

Maybe mice started chewing on the wiring?

 

Haven't seen a single mice for a few years now, can mice climb jackstands? Might be the wiring cuz I do have the Frog harness which is a plug 'n play harness for the VAFC, maybe it got loose?