2002 blazer wont start but cranks over?!
 

I have an 02 blazer, it wont start but it will crank over and you can here it fire, like one spark plug is igniting. It just wont start. About a week ago it was a really moist outside because it rained for about 3 days straight. I started it up and noticed it was missing, Like it was only running on 5 cylinders. I parked it and when I tried to start it it wouldnt start. The battery was really old so me and my dad ran out, got a new one, through it in and tried to start it. It still wouldnt. After 10 minutes of fittling with it it finallly started. I drove it home and parked it. The next morning I started it and it ran fine. Then I got home from school and again, It wouldnt start. Its been a week since it has been started now. I fittle with it every day. My dad thought it was moisture in the distributor cap, I took it off and cleaned it, along with the rotor. It still wouldnt start. I replaced the crank poisition sensor because thats what my autos teacher said it could be. I also changed all the spark plugs. I have no clue what it is. It has fuel delivery, I pressed in the schrader valve on the gas line and gas squirted out. I can smell it in the throttle body as well. I tried starting fluid that didnt work. It also has spark, I tested it. My best guess is that the timing is off on the distributor. The cap and rotor have never been replaced to my knowledge. I bought a new cap, rotor and wires. Im putting them in today after school. If this doesnt work I dont know what to do. Im only 16 so I dont know everything. Im hoping its not an expencive fix, I already spent $200 On new battery, cap, rotor, plugs, wires, and crank position sensor. Also I should mention, Dont tell me to hook and OBD scanner up too it, because when I changed the battery, the terminals were dissconnected long enough to clear the codes. PLEASE HELP. Every reply is appreciated. I really need this thing fixed and taking it to a shop is not an option, I would have to pay to get it towed, and fixed.

You sound like you know what your doing but check to make sure the air filter is on right because one time while I was having work done on my 03 blazer they knocked the air filter off and it would like half start and then shut off . Make sure its dry also my friend washed his and it wasn't dry enough so as soon as it went to suck in air it sucked in the residual moisture and shut off its unlikely but it'd be an easy fix just dry or re attach the filter

I already checked that. I had to take the whole intake off to reach some of the spark plugs. Its bone dry. The filters band new also. Along with the Mass airflow sensor. Thats not the problem, But I'll double check when I get home. Im gonna go through and double check everything

check your fuel pressure. Your pump may work but not pumping enough. should be at 60 to 66 psi key on engine off and only drop 5psi when tthe pump turns off

Yeahhh that could be it my friend has a 97 blazer and had to replace it because her car wouldn't start every time

When I got home I put the cap and rotor on, and it started! :D Yay! But only to find out it has the code P0300 random cylinder missfire. Im guessing its one of my vaccum hoses. The one that connects to the throttle bodys pretty loose. Any other ideas? It wouldnt be the plugs or wires because its random. So I dont know.

Check your "spyder" they are natoriously bad. a number of things can throw P0300 codes though.

Great thing about blazers is they all are very tough!