Battery slowly died and 3 codes came up
 

So yesterday I went for a drive in the mountains and I turned my car off when I was gonna take a rest. I turned on the car after 2 hours because I noticed my headlights flickering. When I turned it on there was no struggle but there check engine light and the car was idling a little above 1k rpms. I also found the steering wheel super hard to move in first gear but it got easier as I picked up gears. I drove down and noticed my car was limping because I couldn’t pass 2.5k rpms or the engine would stutter. When I reached the bottom of the mountain I put the car in neutral and I noticed the voltage dropping till the car died. The battery was completely dead and I had to get a replacement the next day. When I went to read the codes, there were 3 of them: p010c, p0444, and p0447. The car now either doesn’t turn on or turns on and idles at 1k rpms. I would like to add I did install aftermarket intakes (stillen gen 3’s, I do know the car runs lean but I was literally scheduled for a tune in the 5th and read it’s fine to drive on them just jot long term) the week prior but the car was running fine until then. So idk if the car battery dying fried some circuits and threw the codes up or if it’s the intake. I’m about to swap the intakes back to the stock ones to see if that fixes it but can I get some insight on what happened and if the combination of codes means something. Thanks for any help.

Check and make sure you still have an alternator/serpentine belt. I beat you don't. That is why it was hard to turn. No power steering either. Thank goodness for you the water pump is ran by the timing chain.

It’s still there and it’s still tight.

The intakes are most probably NOT the problem - removing them would be a waste of time.

My guess is that the battery is shot.

First thing I'd do is put a VOM across the battery terminals and check the voltage - should be around 12 and a half volts if the battery is in decent shape. Then measure the voltage across the battery terminals when you can get the engine started. If voltage climbs to 14 VDC or so, the battery is probably bad. If volts stay the same or drop, the alternator/charging circuit has a problem.

Most auto parts stores will test your battery for free.

The FSM will have diagnostic procedures.

Changed the battery and volts read 12 and don’t drop, problem is now is I’m still getting codes p010c ,which are for the maf sensors (and I just bought new ones so idk why the code is still being thrown up) and the p0444 which the code reader says is the “evaporative emission system purge control valve circuit open.” Thing is now when I turn the car on sometimes and I try to rev it, it sounds like the engine is about to die and the rpms drop.
It also still idles at 1k rpms and stutters and cant pass 2.5k.

You most likely have a intake leak. I bet one of your newly installed intake connection is loose and unmetered getting into the intake hence the maf codes. I’d start at the throttle body. Make sure clamps are tight

What does the in-cabin voltage gauge read when the car is running? Also, I'd have to agree with Spooler and think it's something related to the belt, too many symptoms with the same common factor.

It reads a constant 12v no dips or anything. And I also agree that it would make most sense because I replaced the maf sensors to address the p010c code but after erasing it and restarting the car the came back up. But then again wouldn’t I be getting a different code if it was a bad alternator or belt?

If it's reading 12volts while running I'd guess your alternator is probably bad (which would explain the heavy steering if the alternator pulley is locking up putting drag on the engine/belt), it should be closer to 14volts. I would ignore all codes until the voltage is corrected, electronics can be sensitive to that and cause false codes.

Damn alright I’ll try to get the voltage right and see what’s up afterwards. I’ll update again tomorrow once I tinker around a little bit.

Nope, swapped alternator AND belt and the voltage looks good. Still giving me codes p010c and p0444. Same idle at 1k rpms and can’t pass 2.5k. Basically everything is the same and at this point I’ve put new maf sensors alternator and belt. I’d also like to ad the sometimes when I turn the car on and give it gas the rpms drop as if it’s about to stall.

Do a throttle relearn. You may have dirty throttle bodies. Clean them before you do the relearn.

Alright so I rechecked voltages because the car is literally behaving the same and idk why but they started reading bad again. I don’t get it, after I first changed the alternator they were fine but now they’re low again. They drop to 11v after start up but on a new battery, alternator and belt. What else can this mean? No way I bought a bad new alternator and belt..

Also the battery connections aren’t corroded or anything.

so at this point i know its an alternator problem and i saw no blown fuses on the battery fuse. Ima take off the alternator tomorrow and go get it replaced and tested before i bring back another one.