P0128 isn't a valid code. Any mods to your Cobalt? What year, mileage? No use changing an O2 sensor if you didn't get a code. Most common cause for multiple cylinder misfire is bad gas or water either through intake or in gas.
Every minute spent angry is a happy minute lost for ever and ever!!!
Drives 2007 Cashmere metalic Cobalt LS Sedan 2.2L auto 1G1AJ55F977161789
Never drive faster than your guardian angel can fly
Mods-nothing to the engine except sea foam to the oil and gas.
Interior LED lights
Changed Sparkplugs with AcDelco @100,000
automatic tranny flush
brakes and pads changed
SS body kit
Check out some of my earlier posts. Never figured out the cause of the P0300 in mine, but we put probably a couple grand into it. And now she's sitting parked since the end of Jan. with what we think is a busted timing chain (at 68xxx miles! ). We changed plugs twice, injectors once, new coil pack, new throttle body, new fuel filter, seafoam (plus another I can't remember), dry gas, cleaned MAF sensor. Did absolutely nothing to curb the misfire, then one day I drove her to work, parked her a few hours, and on my lunch she had a knock that made her sound louder than the 72 IH pickup the hubby is restoring! I feel for ya...That P0300 can either be a piece of cake to get rid of or a b****! I hope in your case it's a piece of cake!
Yah it's a shity deal, dealing with this code. Especially when you try to maintain it with with routine updates on a college budget. Oh well, we'll just find out when something breaks haha:S
I really hope you didn't just jinx yourself!! Something broke on mine! Not sure what, but leaning towards something in the timing. Even if it's just the chain, these things have interference engines, so we're sure the engine is pretty much shot. She was fine on my way to work, and on my lunch she had a knock that made her louder than the 72 pickup my hubby's restoring! We've got a guy that can get us an engine and replace it for about 6-700 bucks (plus some body work trade from my hubby), so we're going to do it, but timing right now just sucks. We ended up leasing a 4th gen CRV so we have some time.
I'm not sure what's wrong with her for sure, but a mech buddy of my hubby said a while back that the timing might be off, causing the misfire. (This was back when she was still drivable lol.) I'm starting to think that it was bad before, now just way worse. We'll see here when we pull it apart more....
i seafoamed my fuel and brake booster line a couple months ago with no problems. just curious did you change the oil after you seafoamed it? also did you put seafoam in a vacuum line or JUST the fuel and oil? did you have a full tank of gas when you put seafoam in the fuel?
check your spark plugs and wires while youre under there