1999 Chevrolet Blazer help please!

There's two common things to look at. First of all, depending on the type of fuel injection system you have, some GM engines won't start if the fuel pressure is as little as two pounds low. At roughly 50 pounds, that's not much leeway. My vehicles run around 50 pounds and will run fine down to as low as 20 psi. That is common and makes it hard to believe that two pounds can make that much trouble on some GM engines.

The next thing to consider is if the intake air temperature sensor is reading correctly. If it's reading a higher temperature than it should, you won't get enough fuel for starting.

Hahahahaha. I'm not a "sir"! That was my father.

Holler back with the solution if you find it.