Alright here it goes. I have a 1986 Subaru BRAT GL. It has some incredibly irritating idle issues. It will idle fine just after start up and around town, about 700 RPM just like the factory manual says is the sweet spot. However after getting up to highway speed you step on the clutch to shift from third to forth gear, and instead of the engine speed dropping it shoots up to nearly 5000 RPM. If you need to slow down to turn off the highway, and you step on the clutch it will "idle" at around the 5000 RPM point again. It comes and goes, I can make a trip from point A to point B with it having this issue. Then when I make the return trip to town and have to go to lower speeds, sometimes it will begin idling correctly for no apparent reason. We have checked for vacuum leaks and believe we have eliminated all the lines as possible cause. Whoever worked on it last had replaced the high and low speed lines without putting in the required orfices, so we fixed that with high hopes and got nothing. I have done lots of research and have several other things to try. Such as cleaning the EGR valve, doing a complete rebuild as I know it likely needs it, and replacing the the whole entire Hitachi if when I pull it again the throttle shaft bushings are shot. I will keep experimenting, but any advice could help. As for the people that will likely insist the only solution is to chuck the Hitachi in a bin and get a Weber, I might do that in the future but I want to keep this car as factory as I can. Any help is appreciated.