will_s95 Posted June 1, 2013 Report Share Posted June 1, 2013 The tires are all good, I just changed the air filter a little while ago, and I'm not carrying any extra weight. I still only get about 17 mpg average The engine only has 74k and runs great, but I have read on here that a dirty EGR valve can really hurt gas mileage. Where is that so I can check it? Is there anything else I can check? Quote Link to comment Share on other sites More sharing options...
RobertISaar Posted June 1, 2013 Report Share Posted June 1, 2013 SO many things can kill fuel economy on a W... alignment? brakes sticking? coolant temp sensor? exhaust, particularly the cat? injectors? O2 sensor? thermostat? SES light act normally? does all of the cluster act normally? someone ghetto-rig the fans to be on whenever the ignition is? what kind of fuel? what kind of oil? how does it look after ~500 miles of driving? trans act normal? tire pressure? and finally, let's get to the human factor... what kind of route do you deal with? how do you drive it? even in nearly all-city driving in the middle of winter, i don't think i've ever gotten under 20MPG with the MC. as for EGR: look at your throttle body, now look about 6" toward the firewall, should see 3 "towers" with an electrical plug in the center of them. that's the EGR. IIRC, 2 10mm bolts hold it on, you'll be able to inspect both the EGR and the EGR passage. Fehl did a good writeup on that, i just don't remember where it is ATM. Quote Link to comment Share on other sites More sharing options...
Swarzkopf Posted June 2, 2013 Report Share Posted June 2, 2013 Disclaimer - I don't know jack about your particular model vehicle/engine. LOL That said, one of the biggest culprits I've noticed over the years that causes bad gas mileage on late models is a dirty MAF sensor. Not sure what type of MAF you've got, but if it's possible to clean it with a bottle of aerosol MAF cleaner, it's certainly worth trying. Other then that the stuff that Robert mentioned is great. A poor state of tune (plugs, wires, O2) can kill gas mileage really fast. Quote Link to comment Share on other sites More sharing options...
RobertISaar Posted June 2, 2013 Report Share Posted June 2, 2013 95 3100 = no MAF. Quote Link to comment Share on other sites More sharing options...
will_s95 Posted June 3, 2013 Author Report Share Posted June 3, 2013 Robert, thanks for that list. Easy for a total noob like me to understand. Everything on there checks out fine. I do not know the state of the spark plugs themselves, but the wires look fine. I will check the EGR valve tomorrow. Ill throw up a picture of what i'm about to take apart tomorrow to make sure it's the right thing. Quote Link to comment Share on other sites More sharing options...
RobertISaar Posted June 3, 2013 Report Share Posted June 3, 2013 wires look fine = not necessarily fine... if you have a multimeter, ohm-check them, if you get any odd readings(~5,000 to 10,000 ohms would be normal), move the wire around while still connected, if the reading changes noticably, it's a wire that's about to fail completely. Quote Link to comment Share on other sites More sharing options...
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