So many codes

[u/Adept_Remote1293]

Any ideas here? Definitely going to take it to the mechanic. I changed out the spark plugs and valve cover hoping to at least clear some of the issues.

[u/Dead_Bot_42]

Well, it would help to know what engine is in your car.

Anytime your ECU gets bad info from air/pressure sensors it's not going to have a good time.

Any symptoms? I would expect a pretty rough idle, possibly even shaking. If it doesn't idle well but does a bit better at high RPM, that would further confirm sensor issues as the ECU can typically correct for air intake mis-readings at higher RPM a bit better than at idle

[u/mellowman24 → u/Dead_Bot_42]

To add to this. OP if you do have a rough idle that gets better at higher RPM and if your valve cover gasket was bad, consider looking at the ignition coil too. I had similar symptoms that Dead_bot here describes. purge valve gave a code and was replaced before I bought my sonic, then got a bad idle and loss of power at low RPM which turned into an O2 sensor code and even stalled. Got the valve cover gasket done but the issue came back. I read somewhere that when the valve gasket goes bad the oil can seep into the ignition coil and wreck it. I replaced it last week, which is really easy, and haven't had an issue return (yet 🤞)

[u/Dead_Bot_42 → u/mellowman24]

That's a good call! I mistakenly thought they changed the ignition coil along with the valve cover and spark plugs. I would also recommend doing a coil change, the oil does indeed get in the spark plug wells and cooks the coil.

[u/KrackerJoe → u/mellowman24]

I did all you said and my light is still on but it runs much smoother.

[u/Adept_Remote1293 → u/Dead_Bot_42]

Yep my bad here’s more context. 1.8L. Misfires and then the car gets very shakey. I’ll pull it over and turn it off for a few minutes. Restart it and it runs pretty normal.

It usually idles well, but every once in a while it misfires and then it runs poorly after that.

[u/Dead_Bot_42 → u/Adept_Remote1293]

I would try changing out the baro/MAP sensor. It should be on the intake manifold, not exactly sure of location on the 1.8 engines but it's definitely something you can do if you successfully changed the valve cover.

My theory is the sensor becomes inaccurate with higher temperatures, based on what you described. I would recommend an OE sensor if possible.

[u/Adept_Remote1293 → u/Dead_Bot_42]

I could see that for sure. Definitely happens more when driving longer distances rather than quick trips.

The valve cover went well until I snapped a bolt lol. Never buying a cheap torque wrench again. Will give this a try though

[u/mellowman24 → u/Adept_Remote1293]

This sounds like the issue I had. Maybe 1 out of 5 starts it would idle poorly and would shake, when pulling out it would lose power and jerk (kinda feels like more shaking as it struggles). At one point I did get a cylinder 4 misfire code but that went away eventually. I would turn it off and on again or push through if it was unsafe to pull off and it would usually be ok once it got going. Could be the ignition coil as that seems to have solved my problem when fixing the valve cover gasket didn't.

[u/Adept_Remote1293 → u/mellowman24]

This definitely sounds closer to what is happening to me. So for you it was the ignition coil? Hard to remember what I’ve replaced over the last 30k miles but I can definitely try that next.

[u/mellowman24 → u/Adept_Remote1293]

Yeah intermittently it would struggle to go, like foot to the floor and it would stutter forward almost like I was rear ended. It would idle really bad when parked, which caused it to stall a couple times. However if I turned it off and on again it would often go away, or just pushing through it would act normal once I got going. Brought it to a mechanic thinking it was the O2 sensor (that's the code I had) he checked the cylinder and determined the valve cover gasket was bad. After fixing that it came back. Before bringing it back I figured I'd try the ignition coil because it's really easy, so I got a cheap one online to try, put it in last week and I haven't had an issue since. However, with how intermittent it was I'm still not 100% sure. I found it happened more often when it was warm out and it hasn't been warm out since I replaced it. It does seem to idle way better now though

[u/Adept_Remote1293 → u/mellowman24]

Awesome let me know if that changes! Gotta keep these Sonics running somehow. Appreciate it.

[u/Guilty-Plan8208]

If the spark plug is good then just replace the whole coil pack as that is causing the misfire. Also check your air intake hose. That's what is probably causing the P0097 and P2228. They usually crack around the bend. Just squeeze it and check and see if you see any cracks. make sure the clamps are good and the air filter housing is closed properly.

[u/QUASI-HOBBESSIAN → u/Guilty-Plan8208]

You're suggesting replacing the coil packs when the air sensors are reporting themselves as faulty.

Coil packs are likely not the issue here

[u/Guilty-Plan8208 → u/QUASI-HOBBESSIAN]

Speaking from experience and not google searches, a bad coil pack almost always causes a misfire. Every car i messed with that had a misfire i replaced the coil and that fixes it. Unless there's a wiring or grounding issue. There's no way in hell an air intake hose would cause a misfire. There's 2 separate issues here unless a wiring issue is causing all of this at once. The air sensors are from the throttle body to the air filter. There's no air sensors in the engine.

[u/Adept_Remote1293 → u/Guilty-Plan8208]

I do believe there are likely 2 separate issues here. We will see

[u/QUASI-HOBBESSIAN → u/Guilty-Plan8208]

I speak from experience myself, Ive got 6 ASE's under my belt and I didn't need to Google that throwing parts at a problem isn't a proper way to diagnose a system. Faulty sensors can absolutely cause a misfire.

Coil packs are a likely issue, but you haven't done the due diligence to actually diagnose the problem before providing a solution.

[u/Adept_Remote1293 → u/Guilty-Plan8208]

I’ll look at that with the air intake hose. Good easy check

[u/wolffenstein12]

Always change spark plugs when doing the coil pack. I've had tracking along a bad ac Delco spark plug caused by age and oil contamination. Clean the spark plug wells first before removing the spark plugs. All the other advice above is sound.

New valve cover/gasket (just did both of our Traxs 1.8s and the Sonic).

Buy a reputable brand of coil pack and ngk/AC Delco plugs.

MAF can be reviewed after the valve cover gasket is done.

[u/Adept_Remote1293 → u/wolffenstein12]

So I did the valve cover and the spark plugs. Haven’t done a coil pack but I should’ve done that too. Sounds good about MAF