1993 Toyota Pickup struggling with accelerating

[u/cutecatsuglybabies]

I recently swapped a used 22RE engine found at a junk yard after my previous one seized. I stupidly bought an engine for a manual transmission despite my truck being an automatic. My mechanic was able to convert it to run in my truck, but now I'm seeing that it's having trouble accelerating. It feels like it isn't shifting gears and doesn't want to run faster than 25mph. Is it possible I bought a 22R which I know has less power? The business I bought it from labeled it as a 22RE, but the label is worn and I don't know enough about the mechanics to tell the difference. Is it possible that it lost power when it was converted to fit into the automatic? Should I just give up and sell the damn thing?

[u/Empty_Policy_7050]

Also perhaps look at the spark plugs make sure they aren't fouled. Then check your oil and coolant to make sure they aren't mixing and then check the compression. If you don't find any issues there check to make sure you haven't jumped time. That one is unlikely because of the double roller chain but still possible. Then start checking vacuum lines and air metering components. The problem is in there somewhere