viper alarm causing voltage dips at idle?

Hey guys, I've performed a thorough search here and turned up nothing with the keywords I used. My issue that occures now, after installing a viper 5900 alarm on my 06' chevy cobalt, is a drop in voltage just about every time I come to a stop. The voltage will drop from the proper 14V to anywhere between 12.3V and higher. This fluctuates voltage levels for no more than about 2 seconds. Could this quick idle surge in voltage be caused by this alarm installation? Would a bad ground be the culprit here? Also using the XK06 bypass with this install. Josh

Are you using tach sense?

hello did you plug the tach at the injector or coil i had a problem with a ford focus but the idle was off all the time for some reason the car did not like the tach wire so i unplug and use voltage check work fine after that

Yes, I have my tach wire tapped into a fuel injector at the injector wiring harness. As with the Ford Focus, mine is duplicating that process. The car hates something right now. Is there an alternative for a tach wire on my car? Even a way of overriding the tach feature as my car starts quickly every time so I'm not worried about the remote start failing to start the car initially. I live in FL so cold starts are not a concern.

Along with my previous post, I have the jumper for the tach on the threschold setting on the viper brain. Is this the 'tach sense' you were referring to?

I asked you these questions because I've had this problem with tach sensing when the tach is picked up at an injector with European cars such as the Focus, VW Golf and Vauxhall/Opel (Saturn) Astra; all using very similar Bosch based injection systems. The answer is to use an inductive sensor such as the DEI 454T (Ibelieve that's the correct part number).   With this you're not "touching" the ignition/engine management system at all.  Doing this cured that problem in a Golf.