Really would like to figure this one out guys. I got a 90 iroc, with a 305 tpi. I got a code 24 wich is the sps sensor. My tach doesn't work, which I think it's related too. But here lies the real problem. If I let my car sit for 2-3 days and go crank it, it kicks the check engine light on, and acts like it doesn't want to run right. I got new plugs, wires, valve guides and it should run pretty well. If I let it run for about10 minutes an cut if off and crank it, the light goes off, or if I disconnect the battery it goes off, and runs fine. Btw the code 24 is the only code I get, so is this causing the problem, or is it something else? If I crank it everyday, it does not do this. Would the throttle positionig sensor do this also? Thanks in advance.

 

If your speedo is working properly, the problem may be in the ECM or CalPac.

Open the ECM and reseat the CalPac.

Also check the tach signal from the dist before & after the filter.