Lower than expected MPG

I see a lot of people are getting between 30 and 40 mpg, but my MPGs seems to suck. I'm averaging between 22 and 25 it seems no matter how I drive. I thought maybe I needed an oil change, but that made no difference. Tire pressure is fine, don't have any performance issues. I am tuned with tsp stage 1 tune but mainly use map 1, no matter which map I use MPGs are about the same anyway. I am stock except performance Cat-back exhaust and Mishimoto Intercooler. Not sure what's going on...

amirza786 said:

I see a lot of people are getting between 30 and 40 mpg, but my MPGs seems to suck. I'm averaging between 22 and 25 it seems no matter how I drive. I thought maybe I needed an oil change, but that made no difference. Tire pressure is fine, don't have any performance issues. I am tuned with tsp stage 1 tune but mainly use map 1, no matter which map I use MPGs are about the same anyway. I am stock except performance Cat-back exhaust and Mishimoto Intercooler. Not sure what's going on...

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I averaged 43mpgs on a road trip from Dallas to KC

City driving is different, though... I feel like the only way to get anywhere close to 30+mpgs is to shift at 3k and use 5th gear for cruising between ~40-50mph. Of course, this then takes all the fun out of it!

I noticed for highway driving, the best MPGs come from keeping the engine at around 2500rpms in 6th gear, which correlated to ~65mph. Every engine is different.. My TL got the best mpgs cruising in 6th at 75mph.

My engine is all-stock too, so I can't speak on how an exhaust, intercooler and tune will affect performance/fuel efficiency.

Monitor fuel trims and see if you have an air leak somewhere? A car running lean condition are one of the causes for mpg dip. Hope you find the source of the cause.

quakaroaks said:

Monitor fuel trims and see if you have an air leak somewhere? A car running lean condition are one of the causes for mpg dip. Hope you find the source of the cause.

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I'll put my laptop on it and check the fuel trims when I get a chance but I'm not sure what they should be

I'm getting 38 overall and 43 to 45 on the road using cruise control. Hope you find the solution to your problem

Avoid boost. Shift at 2k. You will see much better mpg.

When you want to move, downshift and punch it for a moment. Then get in a higher gear and cruise at 1.5-2.5k rpms in 6th.

Micah said:

Avoid boost. Shift at 2k. You will see much better mpg.

When you want to move, downshift and punch it for a moment. Then get in a higher gear and cruise at 1.5-2.5k rpms in 6th.

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That reminds me of my hybrid driving brother in law who takes his foot off the gas every chance he gets in his quest for mpg's. There isn't a hill he doesn't like

amirza786 said:

That reminds me of my hybrid driving brother in law who takes his foot off the gas every chance he gets in his quest for mpg's. There isn't a hill he doesn't like

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I have a couple coworkers who drive hybrids. I get the same mpg they do, and I take off like a bat out of hell from the work parking lot daily. Nothing wrong with quickly getting up to the speed limit in first or second before skipping a gear or 3 and cruising.

amirza786 said:

That reminds me of my hybrid driving brother in law who takes his foot off the gas every chance he gets in his quest for mpg's. There isn't a hill he doesn't like

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Gotta do what you gotta do. Most of my miles are on cruise control and I get great mileage.

I can get 45 on secondary roads (50 mile trip) without being super careful and only flooring it a couple times. Certain it would be a good bit over 50 on the highway but we only have one highway here in Maine and I haven't been on it yet. One thing I have noticed is that at least on secondary roads, getting the best milage in this SI doesn't always mean being in a higher gear. I have almost never used 6th gear. We don't have the best roads here.

Disclaimer: Using the car's milage indicator. Have not figured it manually.

Just got 40.8 MPG driving 80+ on a work trip to NC but I normally get about 27mpg driving around downtown Charleston SC. All stop and go.

any extra pressure on the gas peddle makes mine go down, it is possible to equal the the mpg of the 1.5 engine in the hatch i had, just very unlikely that i can keep the foot off the gas.
t great mpg seems to end at about 75 mph. as i drive this fast on the interstate, my enemy is a head wind. any decent speed with a head wind and my mpg goes to the dump

On Tuesday I installed a Vibrant resonator to quiet down my 3" performance exhaust, and not only did it quiet things down and make drivability better and more pleasant, but I am suddenly getting good MPG again! For the last 6 months I was getting shitty mileage, averaging between 19 and 23. Since Tuesday after installing the resonator I am averaging between 30 and 38! I have not done anything else. I'm really baffled here...

amirza786 said:

On Tuesday I installed a Vibrant resonator to quiet down my 3" performance exhaust, and not only did it quiet things down and make drivability better and more pleasant, but I am suddenly getting good MPG again! For the last 6 months I was getting shitty mileage, averaging between 19 and 23. Since Tuesday after installing the resonator I am averaging between 30 and 38! I have not done anything else. I'm really baffled here...

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" I'm really baffled here " now that's a funny pun !

Jayceegee said:

" I'm really baffled here " now that's a funny pun !

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No pun intended...ok some pun intended