2000 Alero Strange Problem HELP!

[Drewx62x]

Okay so here's the thing, I drive a 2000 Oldsmobile Alero 2.4L V4 the other night I was out and I drove to a friends house, my car ran fine the whole night all the way up until the point I was leaving, then the car barely started and when it did the car was idleing ROUGH but when I had it at about 3000rpm it smoothed out but had a jerky shift from only 1st to 2nd then rough idle at every stop like it wanted to die (also the TRAC OFF) light came on and stayed on and then blinked on and off at the rough idle. So I went to the Mobil right by her house and filled up on gas (cause I was low) first thinking that was the problem...thats when it got bad and my car wouldn't start at all...So I got it towed home and in my garage...We have worked on it for the past week now and first thing I did was hook up my code reader and got P0300 (Random/Multiple Misfires) anyways here is the list of everything we went through and can not find a problem:
1) Spark plugs and boots and coil (replaced)
2) Fuel Pressure
3) Compression Check
4) Fuel Filter
5) Fuel Pump
6) Ignition Control Module (ICM)
7) PCM
8) CAM Postion Sensor
9) Timing Chain and all the components (the large slide on the right was snapped in half and the tensioner seized up, so we replaced all the sprockets/slides/tensioner/tensioner boot/timing chain) it is now in perfect time.
10) Idle Control Sensor
11) Intake Manifold
12) Fuel Injectors

Then we let the Spark plug cylinders dry out from flooding... and the car wants to start and slightly backfires out of the exhaust but thats it...


So if anyone can PLEASE solve this problem for me I would very much appreciate it bause iect is almost ready to just be towed to the dealership and the car pretty much has to be crapped out for them to even figure out whats wrong with it.

[Iflylow]

O2 sensor causing excessively rich mixture?
Bad MAF or IAT causing same?

[Drewx62x]

I don't know cause I decided to do another compression check and got nothing from any cylinder so i tore the head off last night of the engine and i have bent valves and rods and 2 cracked pistons...new motor now...lol