Hello I am ed, I have a 98 grand prix se 3.1 v6 engine, a repairman just put another 3.1 v6 engine in the car, and now my tach for RPM's is not working all of the other gages work fine just like before the engine was installed, it was suggested to me that maybe the repairman cross the the spark plug wire's when he was connecting the boot to the ignition coils, also, while the engine is not mis-firing, it does idle a little ruff like maybe the wires or cross up, my traction control lite will not go off, could this lite problem have something to do with the repairman reconnecting my power steering hoses?
No, the tach is controlled by the computer and has nothing to do with spark plug wires.
Trac light is a fault in that system, not from power steering hoses.
You had a used engine installed from your description. He did not make the motor and have no history. It is not new, so it will run the same as it did before being removed from the donor car. Have the motor diaged for the rough idle issue and move forward. Warranties on used motors is 30 days for smoke and noise only.