97 Yukon ignition problems

Maybe one of yall could help me out. About 1 out of every 10 to 12 starts... as soon as the motor starts to turn over... i will get this electrical pop and smoke coming from my engine comp. firewall. after the pop (short) i have experienced two different situations. Either the motor will STOP trying to turn over. or the motor will continue to turn over and when it has i have serious idle problems. feels and sounds like several cylinder misfires. ive looked everywhere and cant really find which wire is shorted. ive looked at many diagrams and cant really pin point a circuit that would be causing this problem. Anyone have any ideas??????

What kind of unit are you installing? If you have double checked all your connections, try switching the brain...I have found a lot of times when the remote starter is giving issues of some sort or another in the car it can be a defective brain... Other than that I have never experience anything that you are describing. GOOd luck

comp.= compartment. once it pops i can see electrical smoke from a certain plug on the firewall. the unit that is installed has been in for about three years. Viper. this just started a few months ago. it only happens when its trying to start. it screws with my idle if it starts. sometimes it just kills the starter.

POS GM product, does it happen w the key and starter or just starter

Sounds like it might be a problem with the tach wire.  The installer may have picked up tach at the coil pack on your truck which is at the back of the motor b the firewall.  If that tach wire shorts to ground, then that can cause the problem your encountering.Cause I'm So white and nerdy...

First Class Certi-fried installer