how do i get better gas mileage out of this 4 cyl 5 speed?
My car has 128000 miles.
My car has a manual transmission.
Your vehicle is EPA rated at 23 MPG in city driving and 30 MPG in highway driving. You have stated that you are able to travel 240 miles and your tank capacity is 14.5 gallons. Assuming that you refill the tank after using 12.5 gallons, that means you are presently getting around 19 MPG or 17% less MPG than the EPA city rating. Your fuel economy expectations have to be weighed against actual driving conditions. If the 240 miles you travel are made up of short, less than 5 mile trips, in city driving, when the weather is cold, you may not be underperforming the rated efficiency of the car and, if you "are", it is not by much. However, if the 240 miles is driven non stop on a highway at 60-65 MPH (fuel economy drops precipitously above 60 MPH) then 19 MPG would represent very poor fuel economy, as much as 30% less than the EPA rated efficiency for highway driving. So, you have to judge your present results, the 19 MPG, based on your driving conditions. Once you have made that judgement, if you determine that the efficiency you are getting is well below the EPA rating for the conditions you operate in, common causes of reduced efficiency are low tire pressure, poor alignment, dragging brakes, unperformed vehicle maintenance such as spark plugs, air filter and so forth, overly rich mixture due to O2 sensor faults and/or engine coolant temperature sensor faults, leaking fuel injectors, wrong ignition timing, low engine compression and misfires, stuck open cooling system thermostat, exhaust restrictions, and so forth. If you want all of the possible causes evaluated for a possible resolution of this problem, the recommended service is poor gas mileage diagnostic during which the responding certified mechanic will simply methodically go through all the causes to see which apply in your case. It is typical to find multiple causes by the way, for example perhaps underinflated tires and worn spark plugs. In any event all the many possibilities have to be considered, in turn, in an organized way.