moco65

So I start up the vette this morning and get about 1/2 way down the block and notice the "Service Engine Soon" light is on, on the DIC. What's weirder, is I notice the speedometer is reading zero, as is the instant gas mileage readout. Read this way the whole way to work. Good news (?) is the odometer didn't function either, bad news is that nothing stops the dreaded SYS light from flashing... that worked as "normal".

Only other observation was that the car was idling low - around 500 rpm - compared to the usual 900. Seemed to run fine. Never missed. Ran strong.

Will pull codes when I get home, but the curiosity is killing me as to what could cause the speedo/odo problem.

Anyone experience this issue before?

antfarmer2

What year? Might want to check battery and connections and alt. maybe speed sensor. Check and clean all grounds

moco65

Oh... sorry - that would help. It is a '94. New battery and alternator for what it is worth. Will check connections at lunch.

Appreciate the feedback!

92ragtop

Had a similar problem a few years back on my 92. On mine the culprit was the ECM. Had it rebuilt and that fixed all of the issues.

moco65

Thank you... will pull the codes after dinner and see where that leads...

Thinking it might also be the vehicle speed sensor. We shall see.