With the card/mixer removed how does the throttle bore of the governor look,does it have carbon build up around the butterfly?
In my opinion it sounds like the electronic governor is your problem...just my 2 cents worth.

From what I find in the schematics for this engine and in the manual,this truck has a electronic governor,it is a drive by wire system and the air/fuel mixer(carb) has two TPS sensors in it and a foot pedal position sensor in the pedal,there is no IAC control valve on the engine it is all controlled electronically with the governor/carb,the governor sits under the mixer,same as a velocity governor does but is controlled electronically.....
Wiring for the governor connector:
Pin1 pink/white batt + in
Pin2 tan/orange batt -
Pin3 black/light green analog return to ECM
Pin4 light blue/ dark blue TPS2 input signal into governor
Pin5 light green/red. 5 V Refrence wire into governor to know where butterfly position is
Pin6 purple/light blue TPS 1 input signal into governor

if your hunting for a vacum leak just use WD40 or some type of penetrating oil, thats what i use. I know it can be messy but it will eventually evaporate for the most part and does fill in any leak to give you a chance to listen for any change in engine.
Using anything as flammable as ether or propane is suicide...

This reminds me of back when i heard about service stations servicing peoples Air Conditioners and filling them with propane, sure it will work the same as freon but the HUGE drawback is it's flammable!!!! Get a leak and then spark? BOOM!

get the picture?
use your brains guys... this is simple common sense.

ok as for your engine surging problem?
is there not an air control valve on these trucks? kinda works the same was as an idle air control valve does on a car?
try looking there...

good luck

Hi, Great West,
I would try and check out the error log and just see if any faults are logged this May give a clearer indication as to what is wrong. It would appear that you do not have and idle screw on your regulator as every thing is governed by signals from sensors sent to the ECU which In turn will regulate the fuel system. maybe a sensor has failed or is failing. It sounds like the engine is running a bit rich, maybe the engine temperature sensor is failing and is a common failing but there a few other possibilities, and it's no good getting into a situation of changing sensors and injectors to try and eliminate the problem.

Regards Nero

kevin- you're absolutely right- I dropped the ball on this one. Always have a fire extinguisher on hand. I've never used a propane bottle but sounds like a good idea.

If you MUST use anything,use a propane bottle and DONT light it but turn the gas on and hold it CLOSE to the intake runners and see if it increases in rpm....since the propane is a vapor it won't burn like a liquid would on the engine and cause as big a fireball in case something was to happen....

HAVE A FIRE EXTINGUISHER HANDY....SPRAYING ETHER ON A HOT ENGINE IS A RECIPE FOR DISATER.....I recommend spraying the intake runners with water while it's running and listen for the water being sucked into the intake....ANY flammable liquid is asking for trouble on a hot engine..

Maybe a vacuum leak- spray either all around the intake manifold while it's idling to see if the idle raises while either is present.

Changed throttle body assembly and still surging at idle.

Take the plastic side cover off the throttle body (don't loose the clips, they do fly off when you un-clip them, pull the cover straight off, not twisting or turning) used compressed air, (at a lower pressure than you use to blow up tires, wear eye and breathing protection) to blow the dust and dirt from inside the area the cover protects. then replace the cover and all clip and try the engine speed again.

Hi, Great West,

I would say at this stage ensure your air filter was clean. Then start your truck and just try **** the adjusting screw on the Asian gas regulator, usually only a complete turn in or out when the engine is ticking over and see what effect this has.

Regards Nero

Is this the correct model and serial number for this truck?
Asian fuel system?