Gas Mileage and Performance Issues - Chevy Cobalt Forum / Cobalt Reviews / Cobalt SS / Cobalt Parts
All about MPG All about maximizing your Miles Per Gallon (MPG)

 
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post #1 of 4 (permalink) Old 05-05-2015, 06:57 AM Thread Starter
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Gas Mileage and Performance Issues

Ok, so I have been gifted this little Cobalt from my parents, and we have had it for 4-5 years before it was given to me, and it used to get 21.3 mpg avg., I , know I may rant a little bit here, but just bear with me guys, this is my first thread here. Anyways, back around the fall of 2014, I started noticing her lacking in performance, and at the time the avg. mpg was around 19.8, and that summer, my dumb little cousin had stuck a water hose up the exhaust and turned it on, didn't notice it until it was too late..... and I usually am just a back and forth city driver, the thing only has 41,000 or so miles on it now, and the avg mph and the avg. mpg are considerably low for what I should have, my avg. mph is 17, it never has hit over 20 mph avg, and the avg mpg now is 18.2 and I can never get it back up! It does lack in performance, and that's something I like to have in a car! I timed 0-60 in about 10.2-10.5 sec., and it should be doing it in about 8.5-8.7, it's the 4 speed auto anyway, but I notice a HUGE sulfur smell from the car after it sits for a while and I start it, I usually drive a GMC Sonoma 2.2, and my Cobalt sits in the garage for days at a time. I don't like to put that many miles on it, and it used to be a peppy little performer! I like the car and would like more performance and mpg from it as well. I guessed the lack in performance and the sulfur smell I get at idle after starting it back up after a few days is a problem in the exhaust system, maybe a clogged cat or something else, I don't know! Never has thrown any codes and I use 87 octane pump gas, $2.69/gal. from Sheetz. I would like to fix whatever the problem is so I can spend less on gas!
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post #2 of 4 (permalink) Old 05-05-2015, 08:09 AM
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well the first thing i would check would be the throttle body, i would also throw some fuel system cleaner in it just to try and clean out the injectors. also i would stop using sheetz gas, it has E85 ethanol in it, i know its not a lot but over time it might gum things up.

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post #3 of 4 (permalink) Old 05-05-2015, 08:12 AM
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First of all, welcome! That smell you are getting is a plugged catalytic converter, aka Cat. When those plug, you get bad gas mileage and very poor performance ect.

Now, let me go into a little more depth. The way to get better performance and better mileage is to have better efficiency. The better the flow of the engine the better the efficiency. Check your air filter and your spark plugs. Make sure your plugs are gapped right. Fix that plugged exhaust and use a fuel system cleaner, I personally use sea foam. I promise after all of that you will see a decent increase in efficiency.

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post #4 of 4 (permalink) Old 05-05-2015, 08:20 AM
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Quote:
Originally Posted by Leveecius View Post
First of all, welcome! That smell you are getting is a plugged catalytic converter, aka Cat. When those plug, you get bad gas mileage and very poor performance ect.

Now, let me go into a little more depth. The way to get better performance and better mileage is to have better efficiency. The better the flow of the engine the better the efficiency. Check your air filter and your spark plugs. Make sure your plugs are gapped right. Fix that plugged exhaust and use a fuel system cleaner, I personally use sea foam. I promise after all of that you will see a decent increase in efficiency.
sea foam is best! he is right about the air filter too, if your engine cant get enough air cause the filter is clogged its just going to choke the engine, thats definitely not good.

The Land Shark is coming for you!

Quote:
Originally Posted by Coby7 View Post
His iron was too hot and to big.
Bone stock 2006 Cobalt LS Laser Blue

https://www.yourcobalt.com/forums/veh...ml#post1340434
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