Tach reads 2500-3000 at idle.... Trans shifts too soon.
 

Ok, so my T/A has an issue with shifting that I thnik is due to a sensor or something. The tachometer reads 2500-3000 at idle... It's not actually idleing that high, it sounds to be idleing at 900 or so. I think whatever is causeing the tach to read so high is causing my transmission to shift too soon. I believe it is a 700R4. The only sensor I find that I think it could be is the "Vehicle Speed Sensor", but I'm not sure if that would effect the way the tach reads the RPMs. What else could it be?

afaik, an 84 should not have a VSS, The birds first got them in 85, camaros in 90.
an improper signal from the tach to the ecm MAY be causing the shifting issue. i'd try to get a cheap spare tach and run it off the coil/dizzy to see exactly what the motor is doing and go from there.

Sounds good, I can try that. Thanks!

The tach signal will not affect a 700r4 the only function the ecm has over the trans is the lock up. Your problems are most likely not related.

Hmmm.... interesting. Will have to investigate further.