Is this a blown head gasket?

I have a 96 Suburban 454 motor, C2500. Back in October of 2013 it started missing while driving, at some point while driving it completely shut down on me and would not start. It sat in my driveway for a year until it was towed to a shop. The fuel pump was changed out and it ran just fine until Feb of 2015 when the water pump went out. After that was changed, about a month later it started missing again. I figured fuel pump again due to it acting the same so I changed out the fuel pump again. It ran fine until about a month later when the missing got worse. I would drive down the road and when I accelerated it wouldn't have any power, then it would all of a sudden catch up. I had the check engine light checked and it threw codes for the MAP sensor so I had that replaced. Two weeks later it started doing the same thing, only worse. Once it got warm the RPM's would jump up and down while idling, it would lurch forward while at a stop so I would have to put it in neutral to keep it from doing that. I had the check engine light checked again and it threw 4 codes. Manifold Absolute Pressure/Barometric Pressure Sensor Range/Performance, Manifold Absolute Pressure or Barometric Pressure Circuit Low Input, Random - Multiple Misfire Detected, Manifold Absolute Pressure Sensor Voltage Intermittently Low. Having just had the MAP sensor changed, I was informed it could be something deeper as in head gasket. It was losing water, now it's not. It never ran hot, there is no water on the dipstick or on the oil cap. It did however fail a block test. I put the blue devil in when it first started the missing and it didn't change a thing (waste of $65). I live about 2 miles from work and I used to be able to go to and from work and to and from for lunch and not have any issues. Now, as of yesterday (Monday 7/6/15) after it not being driven since Friday morning as soon as I started it up and accelerated it started missing. I have been told it's a blown head gasket but again, no water out the tail pipe, no water in the oil, not losing water, not overheating. I love my Burb, cargo room and seats 8 comfortably (I have 4 children). Should I just scrap it and call it good or does anyone have a cheaper suggested as to what it might be? Thanks!