Ok, so here is the story I just swapped a 22re from a wrecked 93 4wd i bought for parts into my 84 sr5. The motor ran fine when it was first hooked up, but after driving it about 20 miles the 15 amp fuse under the hood blew so I replaced it. After i did this the pickup runs again put the check engine light wont go off and when you drive the exhaust manifold turns red hot. I checked the trouble codes and it gives me a code 12 (no rpm signal to ecu). So, I replaced the computer with a spare computer I had and that didn't help so next I replaced the coil and igniter, checked timing, changed tps, and the pickup coil from the distributer to the igniter and nothing is making the check engine light go away or stopping the manifold from turnig red. Any new ideas or help would be greatly appreciated.
Thanks