Proform 850 dialing it in closer

I had all the neg's hook directly to the Neg post. they suggested to remove the tach ground form the LM2(blue wire) and move it to the eng block. which helped the tps accuracy.
H'm. I'll have to read up on the LM2 tach signal when I get a chance.
The LMA3 uses a single wire for picking up a tach signal.