The fuel tank pressure sensor is for evaporative emissions, has no bearing on starting and running ability. Before I replaced anything, I would check the fuel pressure, you are looking for approximately 60 psi at key on, and it should hold for close to 10 minutes at a rest(after key off). The crank sensor is a logical option, but fuel pressure needs to be ruled out. If it is even slightly lower than spec, it causes problems with vortec engines. The fuel tank pressure sensor may be faulty, and causing the light, but it will not correct your main concern.
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Monday, April 12th, 2010 AT 9:59 PM