Mitsubishi Repair: 1989 Colt runs rough, valve cover gasket, worn piston rings

Question
Hi,
Background:
I have a 1989 Dodge(Mitsubishi) Colt with manual transmission and 1.5liter motor. It has about 120K miles. It was my son's car, and always ran well.  It sat for about a year without being run, and now my other son wants to use the car.  We put fresh gas in it.

The problem:
The car now runs poorly. It idles smooth with an occasional miss. But when you step on the gas, it dies. Pumping the gas pedal helps, and if you get the RPMs up it will run smooth again with the occasional miss.  But pressing the gas pedal again to rev it up more, will cause it to want to die again and you have to pump to get it up to speed again.

What we have done so far:
1.  New gas tank with sending unit/fuel pump (two years ago).
This weekend we did the following
2. New plugs, wires, distributor cap, rotor
3. New air filter
4. New fuel filter
5. Oil change

It runs better with the new items but not much better.  Are there some sensors that may be bad?

As an aside, their is also smoke coming from the exhaust manifold area. It is not exhaust and the car idles/runs very quietly. I think oil may have seeped through the valve cover gasket and dripped on the manifold.  I think this is a separate problem than the above, but wanted to mention it...

Thanks.
Bob

Answer
Bob,
If you have a sensor that was bad, you would probably see your Check Engine Light come on.  If your check engine light is coming on, it may be a cam angle sensor that is faulty.  It's also possible your ignition timing is off.  Your timing belt or tensioner may be excessively worn and needs to be replaced.

If you are seeing and/or smelling oily smoke coming from your exhaust, that could be caused by worn value seals, valve guides, or worn piston rings.  This can cause low compression and cause the car to idle rough.  I would recommend you have your engine compression tested.
Good luck!