Chevrolet Repair: loss of power 4.3L, mass air flow sensor, vehicle speed sensor

Question
Hi again. On Nov 13 I asked a question entitled "loss of power". Since then I've had the truck checked at another garage and then had the injectors flushed at a third garage. The problem is getting better but it's still stumbling up the hill a little and the light is still flashing when it does so. I bought a scanner and wondered if the following data is helpful:
Stored:    
P0300   Random Misfire Detected
    

MIL   ON
MisFire Monitor   Complete
Fuel System Monitor   Complete
Comprehensive Component Monitor   Complete
Catalyst Monitor   Complete
Heated Catalyst Monitor   Not Supported
Evaporative System Monitor   Not Complete
Secondary Air System Monitor   Not Supported
A/C System Refrigerant Monitor   Not Supported
Oxygen Sensor Monitor   Complete
Oxygen Sensor Heater Monitor   Complete
EGR System Monitor   Complete

DTC for which Freeze Frame was Stored   P0300
Fuel System 1 Status   Closed Loop
Fuel System 2 Status   Closed Loop
Calculated LOAD Value   42.75 %
Engine Coolant Temp   93 °C
Short Term Fuel Trim - Bank 1   21.88 %
Long Term Fuel Trim - Bank 1   3.91 %
Short Term Fuel Trim - Bank 2   7.03 %
Long Term Fuel Trim - Bank 2   6.25 %
Intake Manifold Absolute Pressure   95 kPa
Engine RPM   2322 rpm
Vehicle Speed Sensor   88 km/h
Air Flow Rate Mass Air Flow Sensor   71.35 g/s
Absolute Throttle Position   61.96 %

Thanks

Answer
Hi Jerry.... i can't remember all of what you changed on this 4.3l engine but a random misfire would be in the ign circut.does this engine have a dist.or a coil for each plug, or coil pack. if it is dist. check the ign module. if coil per plug you have one thats breaking down. coil pack would be module under coil pack... do you have a lab scope. if you do hook up labscope and attach amp probe to the power side of the module. or if coils the power side of coils. set up scope so that the parade is slow...say 10ms watch the scope the parade should have a sharpe increase on each fire then curve to down. line up should have no bumps in it then should be flat across the top and then curve down. if i could draw it on here it would give you a good idea but i can't...you can look around the net to find a diagram of what a good setting for the scope would be and what a good coil or module should look like...somewhere in your ign you have a spark problem. not enough to fail but enough to drive you nuts....a lab scope will check inj circuts as well. because the code is a  random misfire it will be more likley in the ign module circut.... i hope this helps