Jeep Cherokee Forum - horribly off topic question

Hello I've been on here quite a bit with my X and since I have been able to do everything I've wanted to do to my X I have moved to an 85 toyota as my next toy. I know I know this forum is for Cherokee and I love my Xj but the folks on the toyota forum have been less than helpful or responsive :(. And the help and feedback I have had from us Xj enthusiasts has been very helpful and just a great group of people. So I thought I would see if anyone here has knowledge on an 85 toyota 4x4 22re code 12. My check engine light pops on at 2200 rpms on a new motor in 5th gear. No power loss no sputtering just the orange glow of the dummy light.. and it goes away above 2200 and below 2000 rpms. Any ideas would be very helpful . Truck runs great even with the light on so I'm kind of inclined to just ignore it. But thank you in advance I know asking toyota questions on a jeep forum is like asking for produce in a hardware store but Cherokee forum has always been so polite and helpful in the past (all of the users I mean) and I am hopeful someone might have a knowledge base on this topic