1998 GMC Jimmy bogs out

Been dealing with this 4 a few years, it comes and goes. Gone threw a few different tecs.
My 98 gmc jimi has this thing where when u hit the gas the rpms jump up and down and dosent excelerate, dose but with a jerky motion, just bogs out, . Some days it works like there is nothing wrong with it and other times it just will not stop.
a code comes and goes. Its a transmision code I have been told. I've taken to 3 different trans places and all have told me that its fine, wich I would think that they would want to put a new one in if they had any reason to do so.
been regular with tune ups, new sensors, spark plugs, fule injectors, trans flush, fule pump and filter.
also it seems to get bad when it is, or has rained.