so about 2 weeks ago i picked up another mitsu,its a 90 with the 2.4 and 5 speed,210k on the odo when it stopped working,about a year ago the guy got the motor swapped out with a lower mileage motor,he said its got about 55-60k on it now,and has receipts from the swap,motor came out of a 91,im having problems with the motor running funne when its at set speeds and idle,it idles rough and spits and sputters when youre cruising at a set speed,but accelerating it has no problems,when you get on it a little it blows a little black smoke,and im getting horrible gas milage,like 8mpg or so and i have no clue of what it can be,help!!!