Running rough

[Texas1987]

So, in the last few weeks, my Cobalt ('06, 2.2) seems to have gone all to hell. It only has 54,000 miles on it.

3 weeks ago I was sitting at a gas station when the bottom dropped out of the rpm's and the check engine light started flashing. Started running half of what was normal, trying to stall. Had no power on take off. This problem was intermittent. Took it to a dealership where they replaced the fuel pump under a recall for the modular reservoir assembly (MRA) leaking. This didn't fix it. Those guys had been assholes, so I took it to another dealership who ran diagnostics, and theoretically couldn't find anything. But they reprogrammed the ECM anyway, because of a TSB stating that this might solve the problem. It didn't. Took it back the next day, spoke directly with a service manager, and magically, when they ran diagnostics again, they showed a misfire on 1 & 4. They replaced the ignition coil pack. This solved the intermittent rpm drop.

Unfortunately, another problem popped up as soon as I fired up to leave the dealership. My idle was rough constantly. Got worse with turning the A/C on. Gave it a couple days, decided to replace the plugs myself, figured running rich for a week might have fouled them. Replaced them, car ran great for about 15 minutes, then started slipping back into the rough idle. Currently, it runs like crap when it idles, acceleration is spotty, sometimes good, sometimes not. But at highway speeds, she'll run and accelerate like nothing is wrong.

The best guesses I can come up with are either 1) something is blocked in the fuel system, 2) I have a gasket leaking somewhere, or 3) there is another TSB about a possible bad ground at g103 causing a misfire (I think this is least likely).

Now, based on the fact that I use good fuel and run fuel system cleaners every couple thousand miles, I think the fuel system is a long shot. And after looking at my motor yesterday, the gasket seems most likely.



http://www.flickr.com/photos/52814116@N06/4868714435/



http://www.flickr.com/photos/52814116@N06/4869329776/

There has been a little bit of crap at that spot for about 20,000 miles, but it being visibly wet is new, within the last two weeks. Which gasket is this? And if you can think of something else causing the rough idle, please let me know.

Additionally, the throttle body has been cleaned since all of this started.