Here is a start. Have the pcm checked to seeif it's sending a signal to start the car if not then see if bcm is doing same as i'm sending diagrams for it. Here is also a tsb from gm that covers hard starting.
NOTE: GM UPPER ENGINE AND FUEL INJECTOR CLEANER is the only injector cleaning agent approved for use with General Motors fuel system components. Other
injector cleaners may cause damage to plastics,  plated metals or bearings. General Motors has completed extensive laboratory testing of GM Upper Engine and
Fuel Injector Cleaner,  and can assure its compatibility with General Motors fuel system components,  as long as the cleaning procedure is followed correctly.
There is also a thing called top tier gas that is not available at all gas companies that have to do with clean injectors. If you do short hops like less than 10 miles driven each way this can effect your car. Check with a dealer for specific tsb for this. It gives the stations where you are in U.S. And CAnada
Image (Click to make bigger)
SPONSORED LINKS
Tuesday, December 27th, 2011 AT 10:13 PM