Joel's engine is unable to power his car the way it used to. the spark plug is working and the engine is compressing properly so what could be the problem

Joel's car is probably with the dirty fuel filter and this is causing fuel supply problem.

Explanation:

The fuel filter is one of the indispensable parts for the good functioning of a car and for the longevity of the engine.

This filter has as main function to filter the fuel, eliminating the largest number of solid residues, also excluding all the water that can be contained in them.  These particles or impurities may be present in the fuel tank or even in the fuel itself and their passage causes high damage to the injection pump of a car.

The mesh of the gasoline or diesel filter narrows as the impurities accumulate and this leads to a decrease in fuel flow. The result of this is that the engine is unable to power the car.