Help with 2009 Colorado diagnostics.

I have a 2009 Colorado with a 2.9l 4 cylinder and roughly 100k miles on it, and it previously showed  a p0442 code( small evap leak). I replaced the gas cap as it the usual culprit, and cleared the code. I only drive it maybe once a week unless I need pick up stuff at home improvement store. It was my daily before the pandemic, but I rarely have to go in these days. The last time I drove it, the CEL showed itself, and I could smell gas when I got out of the truck.  Today, I checked the code, and to my surprise there was a whole list of codes. I am using Torque lite app.

P0455 - evap system leak

P0300- engine misfire

P0101 - maf sensor out of range

P0118 - ect sensor low temp

P0171 - fuel trim system lean conditions

B2aaa - unknown

Do these codes point to multiple issues all at once or is a separate issue leading to all of them? Any insight would be great. Or is the answer to LS swap it? 

How's the battery?   Weak batteries can cause all sorts of issues on electronic cars

The battery is about 4 yrs old, and the truck has no trouble starting even sitting as much as it does.

If you are confident in the battery I'd clean the terminals and check the engine grounds.  There's a lot of engine sensor issues going on there.  The other obvious check would be the MAF, MAF wiring and the air intake for any issues.

First one I'd go after is the evap one.  GMs like to stick their purge valve open, and it can cause a few of the other codes.

Coolant temp is not likely affiliated, but most of the others are potential side effects.

Try searching for the codes here: https://www.355nation.net/forums/i4-i5-engine-drivetrain.9/

or, tell your favourite search engine to look at only that website using "site:355nation.net"

If you can smell fuel, you have a fuel leak.

There is a good chance that the fuel sending unit has rusted apart, which can cause fuel odors as well as leak codes.  Or critters could have chewed through plastic fuel vapor lines.  Or the fuel filler neck could have rusted through.  Or a whole lot of other things....  evap faults are not something to throw parts at and pray, especially with the state of replacement parts.  For GM evap parts I insist on dealer parts only because they are only sometimes bad out of the box instead of usually bad.  And if you are employing the parts cannon method of diagnostics, you are adding problems instead of solving them.

101 and 171 are probably related, I would look for a vacuum leak or something simple like debris from the air filter plugging up the MAF screen in front of the sample tube.  GM MAF failures are very rare on vehicles that are not very old 2.8s, 3800 Series IIs, or 1.4ts.  This is another place where the parts cannon is not your friend, I have repaired a lot of vehicles by fixing a vacuum leak and then replacing the Amazon-eBaynium Bob's Mystery MAF with the old part.  It can also be multiple issues, like an exhaust manifold leak causing the 171 (exhaust leaks pull air in, causing the O2 sensor to get extra oxygen, reading lean) and a dirty throttle body causing the 101 (throttle has to be open more to idle, which causes the PCM to see something wrong when the calculated airflow from throttle position is like twice what the MAF is reading)

edit: I did some searching on the b2aaa code because that is curious.  B codes are body codes (radio, HVAC, etc) not powertrain (P) codes like you should be getting from the PCM.  PCM should not give a crap about anything but powertrain or network communication (U) type things.  A failed blend door motor or open headlight circuit won't cause an emissions related failure so it should not show up in the PCM.  So, I dug.  What I have been able to ascertain is that nobody has heard of that fault code and nobody ever finds it except for people who use 3rd party hardware and software to scan, it is a "ghost" and should be ignored. 

Thanks for all the suggestions. After the gas cap failed to address the problem, I am trying to avoid just throwing parts at it.  I would prefer a simple fix, and I am going to examine the evap system first this weekend.