1983 Jeep Other

I have a 1983 cj-7 jeep with a 2.5L engine with about 10,000 miles on a rebuilt motor. It has been running pretty goodfor a while now and then all of a sudden the other day it started spitting, and wont hardly go over 45 miles an hour.I have already put in the past 6 mnths a new battery, spark pluggs, and plugg wires. It also seems to be blowing out some smoke was black now light grey, mainly upon starting. Someone said the old 1 bbl carb might need replacing. Any ideas please thanks, justin
March 25, 2007.

Could be is it dirty? Maybe some gumout might help. The other thing, could be a clogged converter.

Mar 27, 2007.
Did you check the catalytic converter? If it clogs you will get same symtoms have someone rev the jeep and you check the amount of exhuast from the pipe!
The oter thing is timing, the chain may have jumped a tooth.

Mar 29, 2007.
Also check the egr valve for stuk open condition

Mar 29, 2007.