2002 Envoy XL with 4.2 engine, at cold start up,the engine sounds like a Diesel, on 2002 GMC Envoy

at cold start up the engine sounds like a Diesel for few minute ,when it warms up it is quietes down.
Also when exelerates,have this grinding noise,sounds like a bad bearring .At warm idling,very quiet

Asked by for the 2002 GMC Envoy