1999 Chevy Astro, remote start

I am a newbie installer...I have successfully done a Design Tech remote start/keyless on a 1992 accord no problem.  I moved on to a 1999 Astro van which has Passlock II, no chip in the key.  I put in an Auto-Page 655 alarm, remote start and keyless.  Everything works fine, passlock seems to be good, but occassionally when i use the remote to start the car, it will shut off in about 30 seconds and then SOMETIMES retries  to start it self. 

Summary..............

car starts fine with key, shuts off occassionally after 30 seconds when started with remote..

Any help is greatly appreciated..Thanks

ok, so relearn the tach? 

Stupid question, but how do i do that?? I probably know how to do it but never was taught about "learning" the tach

thanks

ok i checked the tach at the source, it shows life. i probed it from the back of the unit to see if signal was sent thru to the unit and it shows life.  starts fine with the key.  i switched out the brain for another rs-650 and reprogrammed it and the unit wouldnt even get a signal to start the car.  so now im thinking it HAS to be the autopage units.  waiting for their tech support and no answer yet!! 

moral of story----Autopage sux???