I drove my newly restored 22 Coupe today.I took off gently,got up to speed(no troubles)then let up my pedal to go into high gear and the car slowed down,after 100 ft. it seemed to want to stall,so I put it back in low and picked up speed again.Car goes very well in low, but boggs down in high.Doubt that fuel is the problem,because it goes just fine in low.Do I have a trans adjustment problem that old brain is not pickin up?
Actually, try it again and if it bogs on a shift up open the needle valve another 1/4 turn immediately...you just may be surprised.
I had one which did that and no matter how I fiddled with the spark or fuel adjustment it slowed down in high. If I could get it going fast it ran fine. Later when I worked on it for another problem I found the head gasket blown between 3 & 4. Just about 1/4 inch of the gasket was gone. Put in a new gasket and it runs fine. Note, clean out all dirt from the bolt holes in the head. I ran a bottoming tap in the holes and blew out with air. I think the head was not all the way down at that area and that is why the gasket blew. A compression check would have found the problem, but I had no idea that was the problem so did not check compression before I pulled the head.
Is there a chance your low band is adjusted too tight? If so, your car will be "relieved" when in low, and then bog down in high because your dragging on low after shifting. If so, you probaly don't have much of a "free nuetral" either. Just a thought,