2002 GMC Sonoma Truck wont start

Engine Performance problem
2002 GMC Sonoma 6 cyl Two Wheel Drive Automatic

Dear Tech:
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