This is my first post on this forum. I own a 1996 Chevy S-10 Blazer 4WD with the 4.3 Liter Vortec Engine. The vehicle has 151 K on it. About a month or so ago I was having trouble starting it. Once it was started and then shut off for a while (say a couple hours or less) it would start right away. It was only after it set all night would the starting problem occur. Finally during a recent cold snap I ran the battery dead trying to start it, and couldn't get the battery to recharge, so I had it towed to the local Chevy dealer. They replaced the rotor and cap, and installed a new battery. They also replaced a broken evap valve and cleared the "check engine soon" light.(I could then remove the black electricians tape covering it up on the dash). The next day I had trouble starting it again so I realized they hadn't found the problem. I dealt with the problem for another 3 weeks or so and took it back to the dealer. This time I asked them to check the fuel pressure after letting it sit all night (previously they checked it while the motor was running and it had plenty of pressure). Well guess what...the fuel pressure had slowly dropped to nothing overnite. This time they replaced the fuel pump and filter ($720) . The next day after I got it home it started right up. I guess I could have saved a lot of money by changing the pump myself but I dont have a heated garage to work in.

 

There is also a Known issue of water in the CPS (crank case posision sensor) plug for these starting issues

Just a thought for those that might look as replacing the fuel pump is not always the issue.