2001 GMC Sonoma Gas Problems?

E

Eric

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I have a 2001 GMC Sonoma 4.3L V6 my gas mileage is going down. I have keep up with maintenance. I have changed oil and filter, air filter, spark plugs and wires, tire pressures good. Is there something I'm missing?
 
If you are buying " green gas " hahaha. That is gas with alcohol in it ,,your mileage will go down a lot. Look at the pump where buying ,it should say.
Or you should check the compression on each cylinder to see if you have a problem with rings or valves on any of 6 cyls.
 
Those are the first things that come to mind for me. I'd check trans fluid and differential fluid as well.

Depending on how big the decrease is I think it could just be age/high mileage, or if you're in a cold climate, the recent drop in temperature.
 
Check the connections where the plug wires connect to for rust or corrosion and clean them with a wire brush etc.I'd be treating the fuel system with something like STP or Lucas fuel treatment , then after using up a few tanks of fuel change the fuel filter on it. Also make sure that the charging system connections a the battery , starter , alternator , and engine block ground and all other grounds are good on it too.






Hope that helps and best of luck.By the way even a slightly loose belt can cause more fuel consumption or wheels that aren't balanced properly or sticky brakes or a fuel pressure or fuel regulating valve that isn't working correctly etc.

It might not hurt to have a free scan performed on just in case any error codes exist.
 
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