XRipx

Here's the scenario

85 Trans Am
91 L98
T5 manual

I will be driving for about 15 minutes, and the CEL comes on. BUT, only sometimes. Most of the time it never turns on, but every now and then it will.

Anyways I bought a new VSS, changed it out (yellow box behind speedo). Still happens. Speedo still works, speedo cable is brand new. Is there another part to the VSS?

I have a theory. About 4 of the instrument cluster bulbs don't work all on the driver's side. I changed them out, but the connections were somewhat ratty. I cleaned them up best I could, used dielectric grease, one of them started working, 3 still don't. Also, when I turn on my headlights, my indicator arrows (green ones) are always on solid, but the lights outside aren't, and they operate correctly.

Clearly there's some grounding or connection issues. Could it be related to the intermittent functioning of the VSS?

scooter

iTrader: (11)

The yellow box is the buffer, not the actual VSS. I would take a look under the car at the wires from the VSS, could be broken inside the insulation or something to cause it to be intermittent

XRipx

Are you sure? I read the 85 and older Firebirds (with the cable driven speedo) had the buffer and sensor as one unit. I'll check for a sensor on my tranny.

scooter

iTrader: (11)

Oh, sorry, I didn't realize, I am not familiar with the cable driven cars

Dyno Don

iTrader: (7)

It is an optical sensor going to a SD 7730 ECM ('91 L98)