All of the engine woes are related to neglect and lack of maintenance. Example : the car had a fuel pump failure, the shop that did the work called to report that no oil appeared on the dip stick and the air filter was completely clogged. When they drained the engine for the oil change they measured what came out, barely a quart! When I questioned the daughter she confessed that the oil light had only come on a couple times... She thought the light means low oil.
My interaction with the Mirage started about a year and a half ago when the AC failed. That wasn't covered by the warranty and the compressor alone was a 1000 dollars, Mitsubishi is proud of their parts and there wasn't an after market replacement.
A thank you to all that have replied. I'm not sure my course of action, it's repair is beyond my skills. I may invest in a dealer diagnostic, that will depend on the dealer shop rate. I'll keep the forum posted on the outcome.