My 95 chevy silverado with the 5.7 , has a slight smell of gas and some power loss and gas milage has gone down. I have replaced the fuel filter,ignition control module, the catalyc converter, the spark plugs and wires recently due to previous issues.

Thoughts:

You've done a lot of good things to your truck. First, check for codes. Second, ensure that the spark plugs are the same ACDelco plugs that originally came in the truck. Third, consider replacing the coil. Fourth, check/replace the Engine Coolant Temperature (ECT) Sensor--they are supposed to provide a rich mixture at start-up and a leaner mixture when the engine warms up. If they become corroded, they can waste a lot of gas and negatively affect performance.