Truck Wont Start

[sknotts]

Dear Tech:

I have a 2002 GMC Sonoma 2dr and well im lost. First off i bought this used drove it home and around town for about 100 miles no problems alittle hard to start but that was it. I went outside about 2 weeks of truck sitting in driveway and it wouldnt start so i changed plugs, wires, cap and rotor. thinking that was it since it was hard to start when i first got it. they was in really bad shape when i changed them, but when i tried to start it the truck still wouldnt run. so i checked to see if i was getting fuel and i was getting fuel all the way to the injectors, i checked spark and i have fire. so i changed injectors and regulator thinking that may be the problem and still wont start. if i spray crab cleaner in intake it will fire and stay running i can even turn the key off and wait a hour and it will still start now that its warm but after engine cools to outside temp(which is about 60 right now) it wont start unless i use carb cleaner to help it. i pulled regulator off and changed it again thinking i may have gotten a bad one and still didnt change anything. i checked fuel filter and its fine. but i dont have a pressure tester to test fuel pressure to see if pump is not putting out the required spec of 55-61 psi. before i go and put more money in a tester is there anything else that may cause this problem

[rodram]

.. get the fuel pressure tested

.. the older 96 & up Vortec's (5.7L, 5.0L, and 4.3L) needed 61-66 psi

.. not sure about your 2002 Sonoma, but it might need the same fuel pressure

.. fuel pressure it very critical for these Vortec engines or the poppet control valves do not operate properly.

[txab]

+1 on checking fuel pressure

[sknotts]

yes i did check fuel pressure and im at 10 PSI with key on engine off and 40 with key on engine cranking. guess now i know either the fuel pump is bad or low voltage so now im on to check that