Originally Posted by cblt12 (Post 2436004)

dude im going to autozone right now... this has been pissing me off so bad i almost want to hump your leg right now. it has been horrible lately and dies all the time! i love you.

Originally Posted by Angel (Post 2581583)

Hey guys, this is messed right up. I am the guy who originally started this thread and Ive learned alot of good information since my post. I havent driven my Cobalt much since I first cleaned the TB mabye about 500km and it had been running perfect but now its back!!! I have no idea why its sticking again soo soon but luckily enough I had ordered an oil catch tank in which I intend on installing within the next week or so. I picked up the oil catch tank off a seller from ebay for under $40 and I am positive that it will be money well spent. For those of you that do not know what this tank does I will quickly explain. The tank kit will integrate with the hose that connects to the top rear of your valve cover and connects to the air intake. This is the hose in which all the gunk that builds up in the TB comes from. Now with the tank intalled in between the air intake and the valve cover, all of the gunky s**t will collect in the tank with only the air passing through therefore no more buildup of this gunk in the TB. I highly reccomend that everyone having this problem should invest in these tanks not only because it will save having to clean the TB very frequently but also extend the life of your engine. The more this gunk collects some will eventually make its way into the engine and possibly cause some damage to the engine. I would like to also say that I am soo happy that I have been able to help so many of you out there with this problem because it was soo annoying to myself that I was at the point of just trading my car in regardless of the tens of thousands I already have invested so I am very pleased. I will also post pictures of the catch tank once installed.

Originally Posted by umrdyldo (Post 2631799)

This fix all didn't work for me one bit. Nice try though. Resetting the computer only delayed it till another day.

Originally Posted by red06s/c (Post 2633418)

I "THINK" this was more for the ss/sc people. Could be wrong tho.

Originally Posted by red06s/c (Post 2562934)

Ok i just clean mine, took it around the block, and it worked..very well. however; now the rpm's stay up alot longer then before. before the clean the would just fall, but now the stay around 2k before they die down. think i should give it a few days for the computer to adj?

Originally Posted by love my SS (Post 2686840)

i also cleaned my tb and have the same result with the rpms. i cant remember back 3 years ago my car doing this. is this normal? even if i take it out of gear to coast the rpms sit right at 2k? my tb was caked with oil and gunk, black as pitch. had 104k miles on it, so i guess it needed cleaning. didnt have the idle problem, car just started to stutter on me at low speeds and figured it needed cleaning. but would like to know if a guy can damage the springs and stuff inside by manually moving the butterfly while cleaning.

Originally Posted by love my SS (Post 2686840)

i also cleaned my tb and have the same result with the rpms. i cant remember back 3 years ago my car doing this. is this normal? even if i take it out of gear to coast the rpms sit right at 2k? my tb was caked with oil and gunk, black as pitch. had 104k miles on it, so i guess it needed cleaning. didnt have the idle problem, car just started to stutter on me at low speeds and figured it needed cleaning. but would like to know if a guy can damage the springs and stuff inside by manually moving the butterfly while cleaning.

Originally Posted by love my SS (Post 2686840)

but would like to know if a guy can damage the springs and stuff inside by manually moving the butterfly while cleaning.

Originally Posted by rnjmur (Post 2689292)

This is normal. I DO remember back when I first bought the car that the RPM always stayed high when coasting out of gear. It is just that over time since the car stopped doing it you forget that it used to do it.

Originally Posted by love my SS (Post 2689868)

wow...its really hard on the gas mileage...i try to coast alot. but i will say, this car is really running now!!! BIG difference. if you havent cleaned your TB, you gota do it!

Originally Posted by rnjmur (Post 2693107)

Coasting is not as good for gas mileage as leaving it in gear. You will get better gas mileage by leaving the car in gear. Fuel cut-off deceleration - when the car is in gear and you take your foot off the gas the car will cut off fuel and use the vehicle inertia to keep the car running.

Originally Posted by PolishPauL (Post 2694616)

Then why does the mpg gauge go up when i coast? And when u leave it in gear, the car slows down if ur not on the gas so wouldnt that make coasting better.

Originally Posted by arkkornkid (Post 2694850)

from what I understand,
in gear decelleration = fuel injectors shut off completely ...while coasting = your car is at high idle, around 1200 rpms, and still pushing fuel.

so, your mpg's will go up either way, but will go up more during in gear decelleration ....

Originally Posted by rnjmur (Post 2698189)

Exactly. When coasting of course you are still going to get an increase in gas mileage. But by staying in gear the car actually shuts off the injectors so you are getting even better mileage. As an example - when I first bought my car I used to coast down hills, etc all the time. My average MPG was about 24 maybe 25 MPG. Once I learned the car had deccelleration fuel cut-off I started leaving it in gear all the time and only taking it out of gear when stopping or the RPMs dropped below 1250 (of course if still moving like int raffic I will down shift at this point). I now average around 28 MPG and that is 50% city driving and sitting in traffic for an hour every day.

Originally Posted by PolishPauL (Post 2698592)

Even tho i can hear the exhaust, theres still no fuel goin into the engine? I always wondered why manuals get better gas mileage cuz in an auto the rpms drop to 1k as soon as u let off the gas. I know why now. Thanks.

So does downshifting to slow down waste gas? Does it matter how high the rpm's are? Is the fuel automatically cutoff even above 3k rpm?

Originally Posted by HeavyRightFoot (Post 2722685)

Thanks for the Info.
My Cobalt just started with that idle surging problem a couple weeks ago.
Going to get cleaner tonite.

Just Curious.... If you have had or are having this problem, What brand of Gasoline are you using?
Wondering if the problem might be related.

I'm using Phillips, Shell and QuikTrip.