Electrical problems/ HELP!!2003 chevy Silverado?

[m.innovations]

okay, i have a 2003 chevy silverado HD 6.0 litter gasoline.

just stated doing this yesterday and i have no idea where to look now.

it starts just fine, but after i put it in gear and start driving it, when i come to like a stop sign it starts idling really low and eventually shut off while still in gear. changed the battery already and the guys down at my local autozone told me the alternator was still really good.

?!?!?!?!?!?!

any ideas

thanks
okay so i think kenneth is right, but im not sure yet, my buddys dad is a mechanic for GM and he is going to look at it later on today.

however wanted to add that it runs fine at high speeds, so i dotn think its the injectors, its just while in gear at idle, and while changing gears from like drive to reverse at idle.

i am pretty positive its a dirty throttle body if not ill look into the injectors

 

[baldie]

bob could be right. you might have a dirty gas filter or if your light is on then maybe the throttle position sensor or idle air control sensor.

 

[internetbuubuu]

you night want to chek the control module, if it doesn't start up again until later... you might want to check the voltage regulator (built in the alternator) if u need a jump after it dies... you might want to check the fuel filter (replace every 40,000 miles maximum) if it runs sluggish after you start it again... other than that you may have a shorted or disconnected wire in the engine compartment or a fusible link blown...

 

[fazekasrepair]

check to see if the throttle plate is dirty. if so clean it with a soft brush and throttle plate cleaner. at a idle below manufactures specs the alternator will not charge at 14 .7 volts like it should. a dirty throttle plate will not set a dtc and will cause a rough and unstable idle
also I had the same problem on a 2003 with a 5.3l and the repair for it was to take it to the dealer and have the computer reprogrammed with new updates it ran like a new truck.

 

[SJP]

Clean TB anyway long overdue, and it may be the problem, usually if the TB plate is affected you would get a "Reduce Engine Power" on your instrument panel and the truck will go into limp mode. Had that problem with my 2003 4.8, had to replace the TB because the actulator was defective. The ECM will relearn the Tb position after about 50 miles. Also check your fuel pressure, if below 48psi replace fuel filter if pressure is still low may be fuel sending unit.