1993 GMC Sonoma Q&A

1993 GMC Sonoma Question: Where do you connect a tachometer to check the Revolutions Per Minute at an idle

I have replaced the throttle body and need to verify engine speed -
Answer 1
Negative side of the coil. -
Comment 1
There are 5 wires running to two separate plugs, which one is negative, and do I pierce the wire? -
Comment 2
The white wire with the pnk/blk, the other white wire is a digital signal for the instrument cluster, if the tach is digital use that one. -
Comment 3
Thanks a bunch -
Comment 4
I was tied up earlier, No Worries. -
Answer 2
Engune idle speed is not adjustablle! That screw is only a throttle stop, ecm has control over idle through IAC valve!! -