2003 Astro injector flush

Hello,
I purchased a 2003 Astro as a hobby vehicle. Its a 2 wheel drive. Overall its in very good shape and the odometer reads 175,000 Kms. I'm hoping to get some help on how to flush the fuel injection system. I have the tools, and have done them before on older throttle body G vans. (1994 and older) But never have done it on an Astro. So, please correct me if I'm wrong here. I need to pull the fuse for the fuel pump or disconnect the fuel pump connector. Next, pinch the fuel return line that sends fuel back to the tank. Now what do I do next? Do I have to connect a line to the throttle body inlet or can I connect a fitting on the fuel line schrader valve? Any help in this regard would be very much appreciated. I will post how I make out once I feel confident that I know what I'm doing. I realize working with fuel systems can be dangerous. Thanks in advance.

Here is the GM TSB that explains exactly how to flush the injectors. The TSB applies to 1996 through 2002 and also explains the upgrade to a true multiport injection system however, on your 2003 M/L body, the 8th character in your VIN is an "X", which means you already have the upgrade. The flush procedure is the same for both systems.

http://members.shaw.ca/betterthanyoutoo/Sticking%20Poppet.htm

Old Master, thank you for that. I have read the TSB and decided that its too complex for my automotive abilities. I will take it to a dealer and get them to do it. Thanks again :)

You're welcome. If the flush doesn't cure the problem, let us know and we can help you diagnose what's causing the problem. In the meantime you might want to check fuel pressure and leakdown, the results will tell if the fuel delivery system is working properly. Key ON, engine OFF, fuel pump running: Pressure must be 60psi to 66psi and must remain above 55psi for 10 minutes after the pump shuts off.