I recently had issues with my car not starting (2012 SV). Replaced battery, nothing. Replaced starter, worked for a bit but had brake and battery light flashing randomly. Replaced alternator, all these issues are gone. After doing the starter, I have had some issues lingering, and can not seem to find anyone with same issues online anywhere. For starters, some of the lights on my dash do not work. The screen does not work (white screen, not orange). You can shine a flashlight on it and scroll through it and see what it says, but it does not light up whatsoever. Blinker lights on dashboard do not work, nor do they make a sound when they are on in the car but they still all work. Headlight icon does not work, brights icon does not work. Seatbelt, brake, battery, ABS, and a few other random ones are still working just fine. Gauges lighting up fine. Another thing going on is that when I start the vehicle, the gauge arms kind of flutter mildly then do the sweep that they normally do about 5-10 seconds later than before. Everything else electrical is working just fine with no issues anywhere. My other and BIGGEST issue is I have a severe lack of power now. No codes are being thrown at all, and it has been a few weeks. Doing the starter, I pulled the ECM next to the battery and the intake (which is aftermarket). My initial thought was a clogged fuel filter, but I am not sure how that would have happened changing the starter and it explains no other issues. Could it be an ECM plug that is dirty/not seated correctly? Dirty MAF? (I did clean the MAF while I had it off and put it back in, the car also has thrown a code for that years ago and is not doing so now), Possibly an air issue? It feels like it has about half the already low HP the car has, and almost has trouble getting out of its own way. I can rev it out with the paddle shifters to nearly redline and only around 5k RPM does it feel like it is actually going to start moving. It is not so low that it is undrivable, but something is definitely way off. I am looking to get it back to OEM intake as I plan to sell soon, but this issue did not start when I swapped intakes as that was years ago. I will try and get a video of the dash driving tonight to show the slow speed the RPM and MPH climb at if that will help anybody. Willing to try any and everything, thank you maxfam

 

Wow, a lot of symptoms but now we are going to need some data. I agree it is probably electrical in nature and reconfirming the connections on the ecm sounds like a good idea. And make sure the mounts are free from rust as well. After that, lets grab a voltmeter and with everything runninng (lights, ac, blower high, rear window defogger, and stereo) with engine running what is the reading from positive to negative terminal on battery? From alternator to negative terminal, from alternator to engine ground. I know you said new alternator, but new doesnt mean good. These readings should help locate the issue (either bad alternator or poor ground..somewhere!)

If you have acxess to an odb code reader i would very much like to know what your short and long term fuel trims are. As well if any codes are captured.

Those readings should help us narrow things down.
From my own experience, a bad alternator mimicked the poor running performance, especially as it failed with high ac ripple (bad diode)

Please let us know your progress and I am sure others can help narrow down the issues

 

I will get readings today, I checked alternator to negative & battery terminals after replacing alternator & they were well within good range with everything running, but I will do so again to get specifics. Another issue I forgot to mention is the trip meter is resetting every single time I turn the car off, very strange. The odo is continuing to climb as normal but both trip meters reset to 0 every power cycle. I’ll post numbers later today when I get the chance to check