2005 Saturn vue any help please

Hi so I was looking for some help if possible I
have a 2005 Saturn Vue 2.2 L four-cylinder
engine. A couple weeks ago my car started to
sputter whenever at a stop or at idle. I
assumed it was a spark plug issue and I
change them and things were fine for a few
days and the problem reoccurred. What’s
weird is that it’s completely random and
happens sometimes and other days the car is
completely fine and runs normal. I had the
codes read and it came back a random misfire
so I bought two fuel injector treatments and
That didn’t fix it as well. My next step was to
change the coil boots which I did but now the
problem is worse the car barely starts and
runs like hell with an awful idle and black
smoke coming out of the exhaust. I thought
maybe it could be the coil pack going bad but
they are 100+ dollars and I don’t have that
type of money to be taking guesses. I also
thought maybe it could be the coil pack
connector but I wouldn’t know how to tell If
it’s not getting power or broken and wouldn’t
know how to diagnose or fix that. I did the flat
head screwdriver to the back of each fuel
injector I can hear each one pulsing fine so I
don’t think it’s a fuel injector problem. I have
A lead tester and put The alligator clip to the
positive battery post and got green lights on
all pins in the connector except one not sure if
that matters but I can’t find a diagram
anywhere relating to that connector. Any help
or suggestions would be greatly appreciated
as I am at a standstill.

Find a good independant mechanic instead of throwing parts at it. He will save you time and money and diagnose your car properly.

The 2.2 is known for timing chain issues. I know the chain/guides can fail to the point where the motor suffers major damage. Usually it is noisy. Don’t think it is included with gradual motor performance issues. Let’s hope you don’t have the auto trans. The cvt from hell.