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Discussion Starter #1 (Edited)
I'm having issues with my 2007 Chevy Cobalt LT 4door Sedan, 2.2 4cyl, Automatic.

First off; my major problem is the misfire in Cyl 2, throwing the code P0302, which isn't much help because I have replaced Coil packs, Plug after plug. Also, the Traction Service Light is on, My next thought would be to replace or have the valve head cleaned. When the car is in idle, it shakes, then once it you accelerate, going into second it jolts, then gets power from second on. It does make a slight jolt going into third. Keep in mind it is an automatic. Also, my muffler goes "PUTT, PUTT, PUTT, PUTT..." Yesterday evening we did take the throttle body off and cleaned it, MUCH better performance, but still the shaking while idleing and the kind of jolt when switching gears upwards. We have noticed many times after changing the air filter that the old one looks as if it's getting water in it, because it is sort of the light brown color in certain spots. Does anyone know what this could be?

Secondly; My air conditioner...I am not getting any air from the vents, nor defroster. I just replaced my Blower Motor, Blower Motor Resistor, Blower Motor Relay Fuse, still no luck..but you can tell that the Blower Motor is kicking on. Also we noticed the connector for the Blower Motor was melted to the old Blower Motor, with replacing the connector, that leads me to believe it is the Wiring Harness. Is this correct? Is there another fuse I should be looking for? Or anything else?

Willing to try anything, just don't know if we're looking over something. Thanks in advance!
 

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Discussion Starter #5
Thanks so much. :) Just trying to figure things out with it, not much of a mechanic, but can do the work of one. haha. But yes, the compression in cylinder 2 was very low, someone has said maybe a valve replacement. I believe the pressure is supposed to be 190. Very detailed in the above post, so if any questions for more explanation, I'll definitely be around.
 

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First off; my major problem is the misfire in Cyl 2, throwing the code P0203, which isn't much help because I have replaced Coil packs, Cylinders, Plug after plug. Also, the Traction Service Light is on, My next thought would be to replace or have the valve head cleaned.

Or anything else?
I read this earlier and didn't really want to get into this one because you seem to have so many issues at a time. How did you change a cylinder? Did you buy this car new? Have you had the compression checked? Are you sure you don't mean P0302?

The harsh shifting, the traction light and the misfire on cylinder 2 all point to one thing. You have intermittent lost of GMlan on one of the modules, my guess ECM. I would disconnect battery, remove and reseat connectors on ECU and see if that clears anything.

For your A/C you probably broke the lever that moves the trap doors in the heater box, there's a thread in here on what to look for.http://www.yourcobalt.com/forums/problems-service/31118-temperature-mixing-door-2008-cobalt-sport.html
 

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Discussion Starter #10
I'm sorry, I didn't mean cylinder, scratch that..I was in a hurry at work when I posted this, and yes P0302. My friend bought the car used from a dealer with her grandmother, lol, which she found out years later, when trying to trade it in that it had been wrecked, but the dealer couldn't tell her how it had been wrecked. We have had a compression test done, and it was reading 90, not 70 as mentioned above.

I'm sorry, can you tell me where the ECU is located?
 

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In front of the underhood fuseblock, second module.



Remove protective cover.
There should be 2 connectors on it.



In between the fuseblock and the ECM sits the TCM (one connector).



Always disconnect battery before reseating these connectors.
 

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Just pull this lever to the right.



Remember to disconnect battery first.
 

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Discussion Starter #15
is there a certain way this slides to the right?

---------- Post added at 05:56 PM ---------- Previous post was at 05:51 PM ----------

nevermind, got it ;)
 

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Work them in and out a few times to clean the contacts.
 

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Discussion Starter #17
Did this last night. Got everything hooked back up. When I started it the check engine light and traction service light was off, obviously. It seemed to be idling better, but as soon as I put the car in reverse, the traction service appeared, then I took it a little down the road the check engine light came back on. I am going today to have it scanned to see if anything new or whatnot, any suggestions?
 

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Do it again, park the car, post it for sale, and don't let anyone test drive it.

" no refunds " policy. :)
 
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