Q: I have a 2001 Astro 4.3, the service engine light is on, there are no codes on 2001 Chevrolet Astro

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I get about 55 miles to a quarter of a tank of fuel and it sounds as if the engine is growling when it idles (like cherry bombs), been tuned up about 500 miles ago, plugs, wires, cap, rotor, PCV valve, oil, air filter, and fuel filters. lost dazed and confused.
(1) Answer
Time to start asking friends for references to a reputable shop. Do you do any work yourself? was there any change in drivability or performance after the tune up? what brand of parts did you use?