Howdy, I take it from what I know of these models, this has a Live Axle. Correct??
If so, I'm going to think outside the square on this one!
With a live axle, both wheels drive at the same speed, as opposed to a diff drive where when turning, the inner wheel goes somewhat slower. On a live axle, the inner wheel needs to lose traction and spin so that the ground speed can remain the same during the turn. Now if, and I'll use your case as an example, when turning right it runs fine, then I would say the right wheel is losing traction and the drive is provided by the left wheel. When turning left however, I feel that it is still the right wheel losing traction, and because the left wheel is the inner of the turn, the wheel will not rotate at the correct ground speed. This would then cause the engine revs to decrease.
This would then lead to the throttle setting being far to high for the engine revs, and in turn, allow too much fuel into the engine. Hence the symptoms.
So my suggestion is to check that the tread on both tyres are about the same wear and pattern, (diferent patterns give diferent traction), and that the air pressure in both the tyres is the same, about 20 PSI.
I know this may sound strange to some, but this is also where I'd be looking.
