ksink7

Car details: 2005, A6 Quattor 3.2L 150k miles.

I am having quite a few issues that I think could be related, but also may just be a bunch of things going wrong. I am mainly worried about the starting issue. I think the easiest thing to do would be to list out all of the issues I am experiencing and see if anyone can piece together what is actually going on. I would prefer to not spend a ton of money chasing down a simple fix and the dealer is wanting way too much.

Starting Issues:
-Occasionally the car will act like it is dead when I turn the key, (lights come on but no crank) and I will have to just hold the key or attempt to turn it 5-10 times before it will crank at all, at which point it will be really slow then fire up. Whenever this first happened there was a door slightly open so I just chalked it up to that killing the battery, but since that time and it has gotten colder out, this is starting to be a normal thing. When it is really bad it will throw a bunch of lights on, and at times it will cause the fuel to read empty (found a discussion regarding this and was able to pull the correct fuses to reset the fuel gauge). It really seems like it is a dead battery but it is a newer gold battery that was put in when I purchased the car, and whenever it finally starts up the battery level shows full.

Turn Signal/Break Light Issues:
My drivers side turn signal/break light will intermittently fail. Started out doing it just one time and going a few weeks before it would do it again, but it is now starting to do that every time I drive, sometimes not until half way through the drive. (Could a short here be possibly draining the battery?)

Engine Issues:
A few months ago the car started to act like it was missing when at low RPMs, mainly at stop lights. If I kick it into Neutral I dont notice it as much but I think it is still doing it. When I am under heavy acceleration between 30-60 MPH there will be a little stumble and it kind of acts like it is missing bad, but the mechanic said he didnt see any codes saying thats what it was doing. (Dealer said this was a vaccum pump being weak and not producing a strong vaccum, he claimed he couldnt find any leaks anywhere)

From my experience, these issues could either be mechanical failure of the fuel pump/vaccum pump/battery/starter/alternator or an electrical issue, which on these I think could very well be the issue. When I bought the car they had to fix a parking break light, and the first mechanic I took that car too said the engine was a junk yard engine (this was not disclosed to me upon purchase, I also had an issue of the rpms dropping rapidly when hitting bumps when I was driving the car home from the dealer, they said it was a sensor tied to the battery that they fixed after the 4th time taking it in for them to fix) and that there was a lot of spotty work done so I am putting my money on an electrical issue, but I have absolutely not a clue of where to start.