Mitsubishi Repair: 1992 Mitsu Galant, head gasket, water and oil

Question
when the engine is cold it runs perfectly but whenever it gets to normal temperature the revs start to go up and down, "check engine" light goes off, if I step on the gas it wont go faster  than 15 mi/hr, lately it has been "smoking" a lot.

Answer
Vitcente: What color is the smoke the car is smoking, if it is white in color then the head gasket in the engine is weak or has blown. Is the car using water, heating? Have you checked the oil lately and seen drops of water in it? If the head gasket has blown, there is water getting into the car's engine and so now the engine is burning both water and oil. If the smoke is very black in color, then the rings are bad and the engine doing what I call a blow by of oil as it is getting past the rings. If you have a check engine light coming on even for a bit, have the car coded to see what the computer might kick out as to the problem with the engine. As long as your car has no power it would either be that head gasket or the rings are shot. God bless: Linda