I made this thread yesterday after performing an oil & spark plug change at 122k miles, where I ended up putting more oil in my LNF Cobalt than required. That issue has been resolved, and I thank you guys for your help.

Now I'm experiencing something different.

I started my car and drove it around for a little while. I noticed a loud vibration any time I pressed on the gas pedal. It seemed to be coming from the front of the car, so I decided to go back home and check the spark plugs. After inspecting them and concluding I did install them properly, I then decided to take them out and put in the old spark plugs.
My thinking was that if the vibration wasn't present after re-installing the old spark plugs, I would know it had something to do with the new spark plugs. I didn't gap the new plugs after all, so I figured I'd find out the problem.
Well, after re-installing the old spark plugs and driving the car a bit more, the vibration is still present. But I actually drove the car out onto the main street and opened it up a bit. The vibration sounds like it could be from the exhaust!
The car sounds terrible when accelerating in any gear from any speed.

Like I said in the previous thread, I don't know too much about cars. I work on my bike regularly, but the motorcycle is much easier as everything is right there without requiring a jack.
I point this out to say that if you guys suggest I go under the car and look for something, I likely won't know what it is you're referring to. @ my lack of car knowledge.

I am hoping someone has an idea of what might be causing this. I did fill the LNF engine with 6.2 liters of oil instead of 5 liters, but the excess oil seems to have leaked out from the oil filter cap, which I hadn't put on properly anyway.

I still have the old spark plugs installed on the car right now. I just find it pointless to switch to the new ones again since both are causing the same problem.

Any ideas, folks?

 

Video of noise vibs make. If u can scan car. See if u see misfire. That or something came out of alignment when u jacked up the car. Go under and see if tranny mounts and everything are missing bolts or if there are any loose

 

You probably dropped a socket or some tools in your engine bay or left something there...

 

or you are having recourse from putting over a quart more than needed in the engine.

 

Here's the video if anyone is interested:

 

doesn't sound like the engine

Maybe check the heat shield on the exhaust manifold. Does it vibrate at idle? you should be able to search it out with it running. Just pop the hood and move your ears around.

 

Assuming this is the problem, will it eventually go away on its own or do I need to do something to get rid of the noise?

 

No vibrations while idling. My wife left a few minutes ago. When she gets back, I'll start the car back up and have her rev it while I llisten under the hood.

 

I uploaded a video if you'd be interested in watching/listening.

No, I accounted for every tool I used. I'm not missing anything.

 

That doesn't sound like the engine to me. Heat shield or something could be loose. Welcome to the world of Cobalts. All they do is rattle and vibrate. I've got a vibration at random times from my exhaust flange hitting the heat shield under the car. They pop up occasionally and you learn to ignore them.

On a second thought, I know you said you don't feel like you can jack the car up anymore. Get up under thae area you jacked and see if anything's loose that may be causing the rattle.

 

Is check heat shields. On the exhaust manifold and the O2 housing. If it sounds like it's from the back at the muffler as well

 

I doubt you messed up anything permanently by running an extra quart of oil for a few seconds. My engine actually ran its last few miles with nearly 8 qts of oil/coolant goodness (thanks to the morons at the dealership).

 

if you couldnt change the oil why the hell are you changing the spark plugs. lol

 

Everyone starts somewhere. The work seemed easy enough when looking through the How-To guides on here.

 

Yeah, I doubt it, too. It's just the persistent knocking that's bothering me. When I have a day off again, I'll look under the car and see if anything seems off. The Cobalts are such a pain to jack up. I couldn't figure out where exactly to jack it.