Car runs like crap all of a sudden

1995 Mazda 626 2.0 L. Great car until about a week ago. It has no power and milage has dropped from 38 MPG hiway to 10!! New plugs, filters and belts. It doesn’t run rough or stall it just has no get up and go.

1995 was kinda a dark year for electronics in cars. The manufacturers needed to have an ODB-II system ready and working for the 1996 models, so a lot of 1995 models had either an older ECM model that was not very good diagnostic-wise or an intermittent system that still required a special code reader.

That being said, a few things to check that comes to mind is checking the fuel pressure, making sure the pressure regulator is not allowing too much fuel pressure, checking the O2 sensor for proper operation, checking the MAF sensor for proper operation, and using a mechanic’s stethoscope on the fuel injectors to ‘hear’ if one may be stuck open.

The first thing to check for is a stuck open thermostat. If the thermostat is stuck open the engine doesn’t reach operating temperature so the computer stays in the open loop mode. The engine then lacks power and mileage drops.

Or if the coolant temperature sensor for the computer has failed where it’s telling the computer the coolant never reaches operating temperature when it actually does, the computer stays in the open loop mode and the engine lacks power and mileage drops.

Tester