01 blazer with 105000miles and it started to have less power and you need to accelerate just so or it won't get to 55. It also jerks you around if you were an inexperienced driver driving a standard vehicle. this happens and your accelerating and 50 yards down the road. things we've done are:
replaced cadillilitic converter.
replaced plugs n wires
fuel filter
cam sensor

the codes that came up prior to replacing these things are p0341 0128 p0335 p0440

 

P0128 - Coolant Thermostat (Coolant Temp Below Thermostat Regulating Temperature)
P0335 - Crankshaft Position [CKP] Sensor A Circuit
P0341 - Camshaft Position Sensor A Circuit Range/Performance (Bank 1 or single sensor)
P0440 - Evaporative Emission Control System

Sounds like you have multiple issues.

I would replace the thermostat and that should get rid of the P0128 code. If it does not, then the coolant temperature sensor may need to be changed.

For both the CMP and CKP sensors to be out... That would point me towards a wiring issue. Here is a view of the wiring diagram for your truck concerning the CKP/CMP sensors: