buddy at work has a stock 02, he says in the morning after he starts truck, he hears a grinding sound coming from engine. he plugged block heater in not as bad when he done that. could this be a starter , he said he replaced it about 3yrs. ago. thanks

 

Sounds like the starter sticking without hearing it first hand. If that's the case, the starter is not long for this world. New contacts and a plunger may fix it, but if the starter gets replaced, buy a NEW unit! Stay away from remans.

Dave