please help heats up runs bad

[zener]

Hi all i have a problem just did an engine change on my 92 4 runner. idles good but when i take it for a drive it seems to run good until it gets hot then i can put the throttle to the floor and it wont go over 40 k 2500 rpm. engine is rebuilt from auto wrecker i get no engine codes. does anybody have an idea what the problem might be.

thanks very much

Zener