Please help me diagnose the problem described below.
I have a Mitsubishi 3000 Gt Vr4 1991. It has 110,000 miles on it. I have not driven it often for the past ten years. I keep it in a garage under a car cover. Last year I drove it in the garage for storage for the winter. The engine ran great. A few weeks ago I got in it to to go for a brief ride but the engine hardly could run. It appears to be missing and some times even backfires. I did always add fuel stabilizer but maybe I did not run it enough. The engine was so week I had to get it trucked to a service garage called A&M in Kilmarnock , Virginia. gun named Roger worked on it. He has now been on it for two weeks! We have bought many parts from Autopartswarehouse. These are Mass airflow sensor, Oxygen sensors,Power Transistor, Fuel filter, new spark plugs, new spark plug wires,No improvement. We put new high test fuel in the tank. Also just checked the EGR valve and it appears OK. We never did get a new Mass flow sensor to try out so this may still be the problem.