48 volt Golf cart moves about 2 feet then nothing. I flip the switch to tow then back to run and it does same thing.

Electronic throttle control !
DTC P2120: Accelerator Pedal Position (APP) Sensor 1 Circuit
DTC P2122: Accelerator Pedal Position (APP) Sensor 1 Circuit Low Voltage
DTC P2123: Accelerator Pedal Position (APP) Sensor 1 Circuit High Voltage
DTC P2125: Accelerator Pedal Position (APP) Sensor 2 Circuit
DTC P2127: Accelerator Pedal Position (APP) Sensor 2 Circuit Low Voltage
DTC P2128: Accelerator Pedal Position (APP) Sensor 2 Circuit High Voltage
DTC P2138: Accelerator Pedal Position (APP) Sensor 1-2 Correlation

2009 Chevy Silverado P2138 Accelerator Pedal Position


Circuit/System Description
The throttle actuator control (TAC) system uses two accelerator pedal position (APP) sensors to monitor the accelerator pedal position. The APP sensors 1 and 2 are located within the pedal assembly. Each sensor has a 5-volt reference circuit, a low reference circuit, and a signal circuit.
Two processors are also used to monitor the TAC system data. Both processors are located within the engine control module (ECM). Each signal circuit provides both processors with a signal voltage proportional to pedal movement. The processors share and monitor data to verify that the indicated APP calculation is correct.

DTC P0455: Evaporative Emission (EVAP) System Large Leak

The control module tests the evaporative emission (EVAP) system for a large leak. The control module monitors the fuel tank pressure (FTP) sensor signal to determine the EVAP system vacuum level. When the conditions for running are met, the control module commands the EVAP canister purge solenoid valve OPEN and the EVAP vent solenoid valve CLOSED. This allows engine vacuum to enter the EVAP system. At a calibrated time, or vacuum level, the control module commands the EVAP canister purge solenoid valve closed, sealing the system, and monitors the FTP sensor input in order to determine the EVAP system vacuum level. The following table illustrates the relationship between the ON and OFF states, and the OPEN or CLOSED states of the EVAP canister purge and vent solenoid valves.

Follow the wires with a volt meter from battery to gas pedal switch to solenoid. Sounds like a bad micro switch , wire, or bad solenoid.

Verify that all battery cables are wired correctly. Should be in series-- neg to pos , neg to pos etc. Then measure total voltage at the main positive and negative battery posts, should be close to 36 volts. If we are good there then measure the voltage at the small posts of the solenoid when the f/r switch is in either position, the key switch is on and the pedal is pressed. I would do this only if the rear wheels are off the ground. Lets say that you do measure 36 volts there, that would mean the solenoid is probably bad.
Now lets say you don't measure 36 volts. Normally there is a small red wire connected to the main positive battery wire at the charger receptacle, it feeds the key switch, key switch comes back and feeds the micro switch on the back of the f/r switch, then to the positive side of solenoid. So connect black voltmeter lead to main negative and with the red lead measure voltage at solenoid. If no voltage keep working back until you find the trouble.
Assuming you have good voltage on positive side, now we check negative side. You probably have a fan shaped black plastic object mounted on the frame under the seat. It's named V-Glide. When you step on accelerator pedal a micro switch in the v-glide closes and provides negative to the solenoid. I hope this helps.

is there enough power in battery to actually start it, or maybe batt terminals are gunked up and need a clean.

Only the battery side of the solenoid will be live until it receives an energising supply from the control circuitry and closes. In the energised and closed condition both sides of the solenoid will be live.

If an energising supply is present at the solenoid coil the solenoid could be faulty. If the energising supply is absent the control circuitry is at fault. Tracing the fault could be made easier by referring to a wiring diagram.

I would check the pedal position sensor. Do it when it's hot.
Mazda Car 2005-06

• Accelerator Pedal Position Sensor

  Description & Operation
  
  A power supply is applied on the Accelerator Pedal Position (APP) Sensor (main) power terminal from the PCM. The ground terminal is grounded with PCM. When the accelerator pedal is moved from the idle position to the fully opened position, the resistance between the accelerator pedal position sensor (main) output terminal and ground terminal will increase according to the depression.
  A power supply is applied on the Accelerator Pedal Position (APP) Sensor (main) power terminal from the PCM. The ground terminal is grounded with PCM. When the accelerator pedal is moved from the idle position to the fully opened position, the resistance between the accelerator pedal position sensor (main) output terminal and ground terminal will increase according to the depression.
  

Testing

1. Connect a suitable scan tool to the diagnostic connector. Select APP1 or APP2 percentage.
2. Turn the ignition switch to the ON position.
3. Measure the voltage at the PCM terminal and ground with connectors connected:
   
   APP1-8% load or 0.4 volts with the accelerator pedal releasedAPP1-60% load or 3.0 volts with the accelerator pedal depressedAPP2 -8% load or 0.4 volts with the accelerator pedal releasedAPP2 -60% load or 3.0 volts with the accelerator pedal depressed
4. If any check above does not meet the specifications, check connectors and wiring between the sensor and PCM. If ok, replace PCM.
5. If the measured values are outside the standard value range, or if the load % and/or voltage does not change smoothly, replace the sensor.

1. Connect a suitable scan tool to the diagnostic connector. Select APP1 or APP2 percentage.
2. Turn the ignition switch to the ON position.
3. Measure the voltage at the PCM terminal and ground with connectors connected:
   
   APP1 %-31.0-32.4% with the accelerator pedal releasedAPP1 %-69.8-81.8% with the accelerator pedal depressedAPP2 %-20.2-21.4% with the accelerator pedal releasedAPP2 %-58.8-70.8% with the accelerator pedal depressed
4. If any check above does not meet the specifications, check connectors and wiring between the sensor and PCM. If ok, replace PCM.
5. If the measured values are outside the standard value range, or if the load % does not change smoothly, replace the senso

It sounds like your battery is discharged, or you have a poor connection between battery terminals and the starter solenoid relay. You may have a loose ground connection on the frame too.
If you have a voltmeter, test the battery voltage you should have about 13 Volts on a fully charged battery.
If you see a severe drop pushing starter (below 9 volts) battery needs recharging.
If you see virtually no change in voltage....you have a connection issue preventing good current flow.