My 03 sierra has a good battery and new alternator. But when I put it in drive or reverse the volts drop and sometimes the truck dies, a real bitch at a stop light.. anyway when the truck is in park it runs fine only in drive or reverse. The funny thing is I used to have a check engine light on, well after it died the first time the check engine light is no longer there. Any ideas on what could be the problem. ???
