Dale, you most likely will get more and better answers if you start your own thread and give the correct model and serial number for your truck.
That said, how do you define "sluggish"? tor motor speed (max RPM) in neutral? speed the unit runs at top speed while driving? acceleration (motor acceleration in neutral, or in gear)? direction changing?
first guess is the linkage or spool to the trans inching valve.

How about if unit is running sluggish but sets no code.

The procedure to clear the codes is:
turn on key
wait 3 seconds
depress pedal 5 times (approx. 1 sec intervals)
wait seven seconds
hold down pedal until hour meter alternates between hour and code
lift pedal
hold down pedal until only hour flahes

A stop watch is very helpful, as the 3 and 7 second parts are critical,this works better with the engine warm.

By the way I would check the converter with a pressure guage, remove the 17mm plug with a phillips screw that is on top of the converter, pressure should be between 4-5 psi, also open the drain on the bottom of the converter, will have to remove battery for access, there is a 12mm plug. There is also a filter in the lock-off. If the pressure is correct you have eliminated the lp tank, converter , and lock-off as being the problem. If there is no pressure check the lpg relay, just some helpful tips. The fuel pump relay is not used on lp trucks so you have an extra relay in the blue box.

Thanks alot i apreciate the help ill let you know if it works.

The easy but slow way is:

remove the + cable from battery for two hours.
reconect them and redy for the next.

the other 2 ways are:
1. with a PDA and his software
2. a sequence with the switch, accel pedal, but i don't remember the steps.

sorry.

How do you clear the codes ?

E-36 is a LPG fuel pressure sensor malfuntion & E-38 is a LPG vaporizor malfuntion. I'd replace the sensor and clear the codes then see what happens, take a close look at the LP tank and hose also.

I have a code E-36 and E-38.

the complete model and serial # for this unit: MPL02A25LV 9H2715

thanks in advance

Jeremy: we re-tested the coils even though they were new. this code only occurs in the crank mode. it is very intermittent. it does not affect the performance of the unit at all when the code is active just annoyingly flashes all of the lights on the display. this unit has bad a lot of surgery by a couple of different companies in an attempt to repair this and some other issues. this is the only problem that is left and it is nerve wracking. can anyone help?

Leon: i have books on PDF on the way so i might be able to help you later if you still need it.

This code is related to your coils. Check your ignition components. Unplug all your coils and plug them in one at a time the engine will run on one cylinder. If you have a dead cylinder swap coils with another cylinder and see if the problem follows.