Audio express recently did a alarm/sound install on this car (eugh.) driving it the other day the tach was twitching. and the next day it died on me while driving - pull the codes, i get a code 19 which is reference pulse too low, as well as no reading on the tach when trying to crank the car - anyone have any ideas? bad opti? bad ground somewhere?

 

Sounds like a bad ground to me. Is the tach needle "jumping"?
If you could tell us around where they worked on it, we'll let you know which grounds to check.

 

Take it back to the place that installed the stuff and tell them what's up. It's possible they cut a wire or something while doing the install. Or maybe something is shorting out. Make them take care of it since the car ran just fine before you had the work done. They should back up their work.

 

word. exactaly what i think it is too, they worked on damn near everything.. i have not checked the grounds underneath the carpet.. all the others look ok though. ideas?