My Blazer is starting really hard. When I start the truck after it has sat for more than 1 hour, it will start but chug really hard for about 5-10 seconds after startup. Then it clears up and all is fine. It acts like it is really flooded or something. I have replaced nearly every single thing on this thing and nothing seems to be working. I have replaced:

CPI injector (spider, FPR, nut kit, all of it)
Engine Coolant Temp sensor (both of them, the one for the gauge and the ECM)
Entire Ignition System (coil, pick-up coil, cap, rotor, plugs, wires, and set timing)
IAT
MAP Sensor
TPS
Knock Sensor
O2 Sensor

I'm just about to buy a vortec 350 and just swap it out. This thing has been nothing but a PITA for the past 6 months. Every little thing goes wrong with it.

Truck does have a slight amount of seepage from the passenger side front of the head, but there is no antifreeze usage. Every once and a while, you will smell just a hint of antifreeze come off of something when you first start it. The motor does not smoke or burn anything at all. It does not overheat, in fact, it never passes 180 rolling down the road. I am just at a loss. Any help will be appreciated.

 

Have you verified that you do not have a fuel leak (watch the fuel pressure after the pump shuts off)? Also that your fuel pressure is proper? From the sounds of it, it is getting too much fuel to start.