Poor fuel mileage - 2001 Chrysler 300M

Many things can cause excessive fuel consumption. First, make sure that none of the brakes or transmission is dragging, or that the transmission is shifting properly. We had a car in the shop recently that had poor fuel mileage and one of the front calipers was dragging against the rotor. (also check the parking brake). Next, is everything up to tune? Good spark plugs, clean airfilter, good PVC, good Oxygen sensors, check for codes, etc. Check if there is a vacuum leak - (use a vacuum gauge). Lastly, if you have access to one, use a emission tester in the exhaust to see what the levels of hydrocarbons are. This will at least tell you if the engine is running clean. Sometimes poor fuel mileage might be a combination of things which all add up, like under-inflated tires, spark plugs fouled, parking brake slightly dragging and poor driving habits. I can always tell the customers who get poor fuel mileage by how often they need new brakes. Someone who lets the car coast and isn't on the brakes much usually gets much better mileage. Those who speed right up to a red light and then jam on the brakes at the last second usually have at least 20% worse mileage.

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poor gas mileage with any vehicle is usually due to lack of maintenance.
options to try:
replace fuel filter
replace air filter
spark plugs
timing adjustment?
let me know if any of this helps

try changing fuel filter and making sure tire pressure is correct keep your car clean so air can flow freely and try an oil change all these factor into good gas mileage and you could try adding new plug wires to your tune up

The specification is 44-54 Psi. The manufacturer lists the specification with the engine idling.

Also, if fuel pressure is the cause of your problem, there will also be other indicators....

First, it will most likely set "lean oxygen sensor" codes in your computer. Also, your fuel trims will be skewed - I would recommend taking a look at that as well. Skewed fuel trims, poor fuel mileage and hesitation, loss of power, can also be caused by a dirty or defective mass air flow sensor.
Another possible cause of poor fuel mileage and poor acceleration is a restricted exhaust.(Bent or crushed tail pipe or a clogged catalytic converter.)

Hi

As far as the review says the mileage should not falter since it is new as you said. However

These are the causes of a poor mileage in a car:-

Poorly Inflated Car Tires

Car tires that are improperly inflated create significant road resistance and drag on a moving car. A car engine has to work harder to propel a car forward due to this increased tire/road resistance. This resistance chips away at a car's gas mileage.

Dirty Air Filter

A dirty air filter impedes air flow into a car's engine, a process that disrupts normal engine combustion and makes it less efficient. This causes a reduction in both engine performance and gas mileage.

Bad Spark Plugs

Spark plugs are responsible for igniting a car's air/fuel mixture, an event that causes a mini explosion inside a car's engine cylinders. Bad or dysfunctional spark plugs don't fire, or ignite, properly; thus, they affect engine combustion negatively, which in turn negatively affects gas mileage.

Bad Oxygen Sensors

For a car to be at its most fuel efficient, its oxygen sensors, small and electronically operated, automatically adjust a car's air/fuel mixture and have to be functioning properly. Bad oxygen sensors cause abnormal air/fuel mixture ratios, a condition that results in poor gas mileage and poor vehicle performance.

Leaky Fuel Injectors

A car's fuel injection system is responsible for injecting precise amounts of fuel into a car's engine cylinders, where it is combined with air and ignited. For a car to perform properly, a specific amount of fuel has to be injected by each fuel injector into each engine cylinder. A leaky fuel injector wastes fuel by leaking it outside the engine and reducing the amount of fuel that makes it into the engine. This results in wasted fuel and reduced gas mileage.
It is suggested to start with a code scanner to find out if there are any stored fault codes in your car.

Also check this link for some helpful tips:-

http://www.wikihow.com/Increase-Fuel-Mileage-on-a-Car

Please get back to us if you have further query else please accept the suggestion.
Thank you for contacting fixya.com

Sounds like you might have an oxygen sensor problem. Your catalytic converter(s) maybe defective or dirty. That in turn can dirty up the oxygen sensor. A defective oxygen sensor will send faulty info to the computer, interpreting the fumes as cold (even when the engine warms up). That causes the computer to adjust the fuel mixture to very rich, giving you poor gas mileage and the fuel smell. Hope it helps.

there are lots of things that can affect gas mileage. if the spark plugs and wires are worn out, the air filter being dirty, dirty fuel filter, proper inflation of the tires, O2 sensors that are contaminated and performing poorly. the first thing to do would be that the engine is in good working order, as in no check engine light, no misfire, etc. a poorly running engine will put out terrible gas mileage. then you can start with the things i listed.

What is the mileage? "poor" is relative. What was the mileage in the past? what is the mileage now? where do you drive? how long? what speeds? weather?

If the gas odor is coming from the engine, than the problem is most likely a cracked or poorly seated fuel injector.

try a complete tune up and fuel treatment once a month and see if that helps