can not get above 2000RPMs

[plh233391]

i have a 1986 ford bronco II when i crank it, it seems to run fine and i am able to drive down the road at normal speeds but once it reaches normal temp. i lose all power it seems like and i cant get above 15mph and 2000rpms even when i park it and just rev the engine it will not get over 2000rpms it is not smoking and i have already cut the cat off to see it that was the problem and it was not any help is greatly need this car has stumped me
thanks

[Pesty351]

does it seem like is missing or cuttingout?