Worse mileage with synthetic (and Bosch Platinum +4's)?

Well, I think I was a tad premature in my assumption. I just filled up and I got 330 miles out of this tank: only a few miles short of my average.

Well, that's good.

I was going to make a comment earlier about the accuracy of eyeballing the fuel gauge/trip odometer. :)

idk if this will help hooah but the gas guage is kinda weird sometimes...
itll go from full to half real quick but take like twice as long to reach empty. I commute almost 300 miles i think a week between home and school.

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Originally Posted by reddemonx92

idk if this will help hooah but the gas guage is kinda weird sometimes...
itll go from full to half real quick but take like twice as long to reach empty. I commute almost 300 miles i think a week between home and school.

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I've noticed that on a couple cars I've had.

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Originally Posted by hooah212002

I just did my first oil change since getting my car. I put Mobil 1/5W-30 in. I also changed the plugs to Bosch Platinum +4's. I haven't yet went through a full tank, but it seems as though my mileage is worse (so far anyways). I usually get 330ish miles per tank (10gal). I am close to half a tank now and only at 120 miles. How is this possible? I do notice a slight performance increase, but I don't use it. I still drive 60-65 on the highway portion of my route to work (80% highway), and pop it in neutral almost always before coming to a stop.

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Run NGK Iridiums. The Aveo seems to like these plugs.

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Originally Posted by Wolfman AK907

Run NGK Iridiums. The Aveo seems to like these plugs.

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Really? Well, I suppose if I can't get back up to 34/35 mpg I'll swap them, but seeing as how I already spent 25 bucks on plugs and I can't take 'em back, I doubt if I'll change them before I'm sure.

there is a long history of plug questions.. the answer usually results in keeping "oem"..

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Originally Posted by MetroMPG

Rotareneg - how are you monitoring fuel cut mode?

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With a Scangauge 2.

Fuel gauges aren't notorious for accuracy, since even temperature changes can alter the signal from the sending unit to the ECM.

Also - if you were getting XX MPG average, that doesn't mean that you went XX miles for each gallon you used, specifically. If the first half of your tank was all City driving, stop and go, you'd have averaged much less, and used the first half of the tank much quicker, than the second half, which could have been a 200 mile trip on the highway, averaging YY MPG for those gallons.

Something like the above scenario could account for your odd fuel gauge behavior?

You know this if you're watching an SG2, though. I sure could use one of those...

I second getting rid of the Bosch Platinum plugs. They, like many others, appear to only be "designer" parts.

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Originally Posted by petrified.rabbit

Also coasting in neutral uses more gas than decelerating the car. Because the car is fed gas at idle versus cutting fuel until reading the matched rpm according to the pedal (with the momentum of the car keeping rpms above that point). But this is nitpicking onfuel consumption maybe a mile per tank.

My car always has it's best mpg right after an oil change and even feels a little more powerful. But I use conventional as the only reason for synthetic is factory tolerance recommendations and/or to prevent sludging typical in low displacement turbo engines. Even though synthetic is typically benefiticial across the board, I have found in my "cheap" cars it doesn't make a big difference like onewould expect. Especially for the added cost.

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a lot of bad information you are trying to spread.

Synthetic does improve fuel economy, engine life, oil change intervals and engine cleanliness. It is not just for factory tolerances or turbo engines. also when used properly, synthetic is the cheaper oil change seeing it costs 20-40% more but can go usually twice to three times the usual oil change. Anyone changing synthetic at the same interval as conventional knows nothing about synthetic oil and is dumping oil that essentially hasn't even seen 50% of its oil life.

Also, it is a myth that during deceleration that the fuel it turned off seeing it isn't.