You need to pull codes and post them. The codes will still be there most of the time. Getting codes can be done with a paper clip in socket a-b of diag connector while these are crossed count the check engine light codes as two digit. Diffrent time between blinks for first and second digit. - .. 12 --- ... 33

 

Sorry...... I don't get 12, but I DO get 36 and 94. I got those even after I reset it by taking off the negative battery cables.

 

Did you or anyone else conduct any maintenance on the truck? If you did then think about hat was done.

You should have gotten DTC 12. If you didn't then something is up with the self diagnosing capability with the truck.
This is what I pulled off of the net.
DTC 34 24x Crankshaft position sensor circuit error??
DTC 94 - Cylinder Balance Fault #5 Cyl?

I would check and see if you do have a crankshaft position sensor and check the connectivity.

As far as cylinder unbalance I can't answer..

 

Could be that the code was missread:

DTC 36 - Injection Pulse Width Error (Time Long)
Code 94 does not show up in any of my searches for OBD1

OBD 1 code list is linked in my signature.

 

Note: *Trans related DTC(s).
DTC 13 - Engine Shutoff Solenoid Circuit Fault
DTC 14 - Engine Coolant Temperature (ECT) Sensor Circuit Low (High Temp)
DTC 15 - Engine Coolant Temperature (ECT) Sensor Circuit High (Low Temp)
DTC 16 - Vehicle Speed Sensor Buffer Fault
DTC 17 - High Resolution Circuit Fault
DTC 18 - Pump Cam Reference Pulse Error
DTC 19 - Crankshaft Position Reference Error
DTC 21 - Accelerator Pedal Position 1 Circuit High
DTC 22 - Accelerator Pedal Position 1 Circuit Low
DTC 23 - Accelerator Pedal Position 1 Circuit Range Fault
*DTC 24 - Vehicle Speed Sensor Circuit Low (Output Speed Signal)
DTC 25 - Accelerator Pedal Position 2 Circuit High
DTC 26 - Accelerator Pedal Position 2 Circuit Low
DTC 27 - Accelerator Pedal Position 2 Circuit Range Fault
*DTC 28 - Transmission Range Pressure Switch Circuit
DTC 29 - Glow Plug Relay Fault
DTC 31 - EGR Control Pressure/Baro Sensor Circuit Low (High Vacuum)
DTC 32 - EGR Circuit Error
DTC 33 - EGR Control Pressure/Baro Sensor Circuit High
DTC 34 - Injection Timing Stepper Motor Fault
DTC 35 - Injection Pulse Width Error (Time Short)
DTC 36 - Injection Pulse Width Error (Time Long)
*DTC 37 - TCC Brake Switch Stuck "ON"
*DTC 38 - TCC Brake Switch Stuck "OFF"
*DTC 39 - TCC Stuck "OFF"
DTC 41 - Brake Switch Circuit Fault
DTC 42 - Fuel Temperature Circuit Low (High Temp)
DTC 43 - Fuel Temperature Circuit High (Low Temp)
DTC 44 - EGR Pulse Width Error
DTC 45 - EGR Vent Error
DTC 46 - Malfunction Indicator Lamp (MIL) Circuit Fault
DTC 47 - Intake Air Temperature Sensor Circuit Low (High Temp )
DTC 48 - Intake Air Temperature Sensor Circuit High (Low Temp )
DTC 49 - Service Throttle Soon Lamp Circuit Fault
DTC 51 - PROM Error
*DTC 52 - System Voltage High Long
*DTC 53 - System Voltage High
DTC 54 PCM fuel circuit error
DTC 56 - Injection Pump Calibration Resistor Error
DTC 57 - PCM 5 Volt Shorted
*DTC 58 - Transmission Fluid Temp Circuit Low
*DTC 59 - Transmission Fluid Temp Circuit High
DTC 61 - Turbo Boost Sensor Circuit High
DTC 62 - Turbo Boost Sensor Circuit Low
DTC 63 - Accelerator Pedal Position 3 Circuit High
DTC 64 - Accelerator Pedal Position 3 Circuit Low
DTC 65 - Accelerator Pedal Position 3 Circuit Range Fault
*DTC 66 - 3-2 Control Solinoid Circuit
*DTC 67 - TCC Solinoid Circuit
*DTC 68 - Transmission Component Slipping
*DTC 69 - TCC Stuck "ON"
DTC 71 - Set/Coast Switch Fault (Cruise Control)
*DTC 72 - Vehicle Speed Sensor Circuit Loss (Output Speed Signal)
*DTC 73 - Pressure Control Solenoid Circuit (Current Error)
*DTC 74 - Transmission Input Speed (TIS) Sensor Circuit
*DTC 75 - System Voltage Low
DTC 76 - Resume/Accel Switch Fault (Cruise Control)
DTC 78 -Turbo Wastegate Solenoid Fault
*DTC 79 - Trans Fluid Overtemp
*DTC 81 - 2-3 Shift Solinoid Circuit
*DTC 82 - 1-2 Shift Solinoid Circuit
*DTC 83 - TCC PWM Solinoid Circuit
*DTC 84 - Accelerator Pedal Position Circuit Fault
*DTC 86 - Undefined Ratio Error
*DTC 87 - High Ratio Error
DTC 88 - TDC Offset Error
DTC 91 - Cylinder Balance Fault #7 Cyl
DTC 92 - Cylinder Balance Fault #2 Cyl
DTC 93 - Cylinder Balance Fault #6 Cyl
DTC 94 - Cylinder Balance Fault #5 Cyl
DTC 95 - Cylinder Balance Fault #4 Cyl
DTC 96 - Cylinder Balance Fault #3 Cyl
DTC 97 - Cylinder Balance Fault #1 Cyl
DTC 98 - Cylinder Balance Fault #8 Cyl
DTC 99 - Accelerator Pedal Position 2 (5 Volt Reference Fault)

 

there's a different procedure to erase some codes.... it involves the throttle peddle or something. I had to do it but forget how now..... I had batteries un-hooked for 2 days and still had the codes until I did the other thing. Someone here should know what Im talking about.....
by the way... my truck does that to some extent still... I get a long pulse code only when cold. I figure I have the timmimg out and when its cold it might be just enough to throw a code.... but it goes away after the pump warms up a little.

 

well I had DTC 19 because my dumb ass forgot to plug in the connector after replacing the IP. Reset the codes and it went away. If some one know about the throttle reset thing that would be greatly appreciated as to how it's done. One more thing..... can I take a 1997 ECU and use it in the 1994? Wait Strike that 97 is OBD II

 

Code clearing procedure is item 3 in the first post here:
http://www.dieselplace.com/forum/showthread.php?t=16399

And thanx for the expanded code chart HeavyChevy95,I did see that cylinder balance codes are condensed in post 4 of the above link.

 

what did you find out after getting rid of all the codes?