It smells like it is running rich. Could it be the fuel pressure regulator. I've changed plugs and wires. not sure which way to go from here.
The past 2 weeks my truck has been getting very poor gas mileage. on 2002 Chevrolet Silverado 2500 HD
Have it scanned with a real scanner, not a code reader and fuel system pressure checked.
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you might want to get a mech opinion if your not equipped to handle suggested tests
'HAVE' it scanned!