gitfooh

I have a 89 that I swapped in a turbo. I changed the harness , ECU, MAF, turbo sensor, tranny. Starts and runs great, builds boost. When I drive it 1st and 2nd gear really pulls but when I hit 3rd at 3500 rpm it goes to limp mode. Checked for codes , nothing and no CEL. I replaced the OMP anyway. Same thing 1st and 2nd great and hit 3rd at 3500 limp mode. I've been working on this for a couple of years now and would like it running properly before I invest to finish it. !st and 2nd gear is so awesome I would just once like to at least fell what 3rd and 4th can do. Is there anything testing I can do to eliminate what is not causing it?