Nissan Altima 3.5 flashing brake battery light alternator tests good? & THEN

My Nissan Altima 2008 3.5L coupe had both parts of the charging system







tested & both test good that they are fine. The light flashing has been going on







for a bit but since charging system tested fine and it has a new battery we







were stumped. One day I went to accelerate & all the sudden I got nothing. No







response to the throttle. Car never died or showed any signs of having a failing







charging system. Pushed it to the side of the road shut it off & went to start it







didn’t want to start. I had a jump pack so I jumped it and it started & got me







home although at lights it seemed like it wanted to die. Got it home, parked it.







Started it the next day after charging battery to drive to shop to have the







alternator replaced I was going to do it myself but you have to take pretty







much the whole front end off & I work a lot and didn’t have the time. No check







engine light. Did flash a “VDC” light at me after I got it home. When I started it







the next day it was a completely different car. Check engine light flashing







popped 2 codes P177 & PO303 code. The shop is maybe 3 miles from my







house but it was jerking, shaking when I was trying to go, struggling to go 35







mph. I got it to the shop & they say they tested wiring and I told them all of this







and the only thing I’ve gotten back from them is the cylinder 6’s coil is bad. I’m







waiting to hear back about how it drives after replacing that but I don’t want to







get the car back just to have to bring it back or pay for a bunch of “maybe”







parts. Can a bad coil cause all this? Do I need a new alternator even if the







charging system is testing good?? They seem to be completely ignoring the







p177 code but when you look it up all the symptoms are exactly what it was







doing. My Nissan has 120k miles the people before me didn’t take care of it







but I have since I got it. Religious oil changes etc. First check engine light I







ever got from it and usually it’s a nice speedy fun car to drive. Always has.







Even with the flashing 2 lights I didn’t notice a difference in anything. And it







was random sometimes did sometimes didn’t. Never stayed on. Always when







driving for awhile.  Maybe a little sluggish. I need help hopefully someone has







been through this or something similar and can give some sort of insight. I







almost want to take it to a different shop for another opinion. PLEASE HELP