hooRAH said:I think the code will tell you the majority of the information for your problem.
As far as the bad injector line from the dealer, it was an uninformed shot in the dark. Unprofessional and lazy. Total garbage.
Stalling while going into drive is usual an electrical problem. Since you said that the seafoam helped, it may have been that the throttle plate was sticking (common on the toyota motors as well).
I am confused though - you said that the battery light came on. The battery light is not an indication of battery charge, it comes on when the charging system is not functioning properly.
If the problem goes away, then great. I, unfortunately, do not think you solved your problem, because I think that your problem is a poor voltage regulator. A poor voltage regulator can cause the alternator to output an erratic or unstable voltage. This would cause both your battery dash light and an "unstable" reading from the CSK machine, even if the battery is good. On top of that, it can cause the electronics (including the electronic throttle body) to go bonkers.
I think this is where your problem is coming from. I would watch the voltage at the alternator output as you start it and when you put the car into reverse or drive. If you notice that the voltage is unstable, the first thing I would replace is the voltage regulator. Good luck with it!
ghettosled said:the voltage regulator is attached to the alternator on the silverado. when you replace the alternator, a new voltage regulator comes with it. but since its putting out good power and your truck isnt losing power, it doesnt sound like thats the problem in my totally unprofessional opinion. it sounds like something with your throttlebody. either something sticking or a bad vacuum line. cracked or loose.
hooRAH said:Hmm, those voltage readings at the alternator sound okay. Im a bit stumped on this one then. I suppose it could be that the throttle plate was sticking and the Elec TB didn't have enough torque to get over the "stick" to open it, but Im stretching my understanding of them at this point. If this were the case and the seafoam cleared it up, then great.
Wouldn't explain the battery light though. Mabye they sold you a battery was bad? Ive never heard of it happening though.
Sorry, I think my experience runs out here. Let us know as more symptoms arise. BTW, you can get codes read for free at autozone.