thewhiteguy1 Posted April 25, 2011 Report Share Posted April 25, 2011 i got decent gas mileage when i first owned that car for a long time. 19/25. no recently i have been getting 16/21. with the gas prices i need this go back up. nothing has changed in sense of mods, except for wideband. I replaced o2 sensor, maf etc. wideband sensor is 6" in front of the o2 sensor. could this be causing the drop??? also, am running 91 because there is no 93 in california. am thinking of getting meth. will this help?? Link to comment Share on other sites More sharing options...
bergmjs Posted April 25, 2011 Report Share Posted April 25, 2011 How old is your ignition system/filters? Old plugs/cap/rotor/wires and clogged filters (fuel and air) can cause a decrease in mileage. Link to comment Share on other sites More sharing options...
Che'_Moderator Posted April 25, 2011 Report Share Posted April 25, 2011 Sounds like more ethanol in the fuel... Link to comment Share on other sites More sharing options...
thewhiteguy1 Posted April 25, 2011 Author Report Share Posted April 25, 2011 How old is your ignition system/filters? Old plugs/cap/rotor/wires and clogged filters (fuel and air) can cause a decrease in mileage. all of it is brand new within 3k miles. not fuel filter though. may get a new one of those. Sounds like more ethanol in the fuel... cause of california rules or?? Link to comment Share on other sites More sharing options...
Che'_Moderator Posted April 25, 2011 Report Share Posted April 25, 2011 Doubt cap and rotor.... if anything I would say O2s Link to comment Share on other sites More sharing options...
thewhiteguy1 Posted April 25, 2011 Author Report Share Posted April 25, 2011 Doubt cap and rotor.... if anything I would say O2s Brand new o2 sensor less then 1k miles and no change Link to comment Share on other sites More sharing options...
Spanky Posted April 25, 2011 Report Share Posted April 25, 2011 Tires and tire pressure? Link to comment Share on other sites More sharing options...
thewhiteguy1 Posted April 25, 2011 Author Report Share Posted April 25, 2011 Tires and tire pressure? 205/45/17 front, 225/45/17 back should be at 34ish front/31ish back, what ever stock settings are Link to comment Share on other sites More sharing options...
831t5r Posted April 25, 2011 Report Share Posted April 25, 2011 Air filter? Driving style change? Link to comment Share on other sites More sharing options...
thewhiteguy1 Posted April 25, 2011 Author Report Share Posted April 25, 2011 Air filter? Driving style change? new in last 500miles. haven't changed since i got the car. Link to comment Share on other sites More sharing options...
Che'_Moderator Posted April 25, 2011 Report Share Posted April 25, 2011 Tire pressure sounds a little low but still say fuel Link to comment Share on other sites More sharing options...
renns Posted April 26, 2011 Report Share Posted April 26, 2011 The air filter used to be the big culprit back in the days of carburetors, since the air restriction caused changes in air-fuel ratio. Now with closed-loop efi systems, that's a non-issue. A restricted filter will limit the max. power output of the engine, but won't affect fuel economy. The fuel filter issue is similar. So long as fuel is able to be delivered to the engine at adequate pressure, it will operate fine. If the fuel filter is plugged enough to cause issues, you'll notice a misfire condition or hesitation under heavy acceleration when fuel demand is highest. That mis-fire will likely throw a check-engine code as well. Under cruise conditions, the engine will still run normally. As you've noticed a significant drop, here's where I'd look: Vehicle Condition: - tire type, inflation - wheel alignment - engine oil - use recommended weight - heavier weight oil will increase consumption slightly. - check engine codes - fix any faulty components/sensors - particularly coolant temp, airflow, and oxygen sensors. - aero drag issues - remove roof racks, broken/missing front body and under-body panels, CB antenna. - make sure proper thermostat is installed - running colder than stock thermostat can cause engine to run permanently in 'warm-up' mode. Driving style: - avoid aggressive accel, higher average speeds - ban teenage son from borrowing car. - avoid idling - no drive-thru's! - avoid short trips - cold starts use far more fuel than when engine is up to operating temp. I think that cover's all the basics for modern fuel-injected engines. Link to comment Share on other sites More sharing options...
KS855R Posted April 26, 2011 Report Share Posted April 26, 2011 What Octane are you running! I run 89-91 and always see better numbers but also try shopping around for gas. I find that if I use a certain gas station I always see better numbers and I dont drive nice :-)I guess I should read the whole post, meth might help a little if you are running high boost but if you are in the 12-14psi I dont see it doing much. Try different gas stations and see what you get. Link to comment Share on other sites More sharing options...
FCP Euro Posted April 26, 2011 Report Share Posted April 26, 2011 Sounds like more ethanol in the fuel... This is a hugh reason my mileage went down in my SR. That is why I only use Shell here in NJ. It is one of the only stations that does not add ethanol to there fuel. Link to comment Share on other sites More sharing options...
thewhiteguy1 Posted April 26, 2011 Author Report Share Posted April 26, 2011 what percent ethanol is too much? Link to comment Share on other sites More sharing options...
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