I currently have some issues with my car, check engine light is on and does drive okay. But after a while of driving it and sitting in traffic, I noticed it was having rough acceleration going into 2nd and 3rd gear. It didn’t do that before when the engine was cooler so I’m not sure what’s going on.
Also, the restricted performance message came up. I checked the air mass flow sensor and it appears to be functioning. I am going to check the intake manifold gaskets today, along with checking if the hoses are intact.

 

I'd start with code P0303. That a misfire on cylinder #3.

Soapbox mode:

If the computer has set a misfire code, please be aware "misfire" wasn't the best terminology that could have been used. Misfire sounds like an ignition problem, at least to me, meaning the fuel and compression were there, but for whatever reason, the required spark was missing or weak. This might lead a good-looking aspiring mechanic to troubleshoot the daylights out of a perfectly good ignition system. I do not care to discuss how I know this.

In OBD-speak, misfire simply means one or more cylinders is putting out low power compared to the others. Pretty much anything affecting the output of a cylinder can set a misfire code. It can be low compression. It can be a valve not opening fully. It could be a clogged fuel injector. And yes, it could be an ignition problem, too, but don't overlook the other possibilities, too. [/soapbox mode off]


Code P1316 is what I'd call a secondary code. It's only set in conjunction with other misfire codes. It means the emissions are high on bank 2, caused by the misfire on cylinder #3.

Same with P0174. It means bank 2 is running lean, probably also caused by cylinder #3.


For P0303, I'd pull the coil and inspect for oil in the plug well. If clean, swap the coil with another from a known-good cylinder and see if the fault follows. If so, the coil was bad.

 

That's why the codes PDF (workshop manual) describes all the known causes of those codes - and the list is definitely not just what might, say, 30 years ago, have been called a misfire. The workshop manual / codes PDF - essential reading. Free to download.

 

So I ended up taking the intake apart and checked the cylinders. I was surprised to find that cylinder 3 (Bank1) and cylinder 4 (Bank 2) were all funky on the inside, so I changed the ignition coils and the spark plugs for those two. I cleaned the rest of them. I also went and bought me a Bluetooth obd2 scanner, and I found another code. p0702, which has something to do with transmission. This car has kind of turned into my little very own nightmare. But the check engine light went off and the car drives better than before, no hesitation and no misfires. But now the transmission is what I have to worry about.

 

Don't worry about the trans - yet - because it may just have been upset by the misfire (which the trans sees as an unexpected jerk). If you've fixed things the trans code may not occur again.

 

You could just clear them and see if anything comes back.
If you do all the monitors will need to re-set so if you need an emissions test in the next couple of weeks it may not be wise.