Nasty275ss

Hey There, Yepp I had to resort to the forums for this because in my 15yrs of Auto Mechanical Exp. Ive never had any sorta trouble like this lil I owned my first AUDI haha. I do love the car though and I'll try and keep this long *** story short....Bought an 04 A4 Quattro 6spd 200k miles back in Oct 2017 and drove it for a month without probs but as it got colder out I noticed I didn't have heat...Replaced Thermostat, J Plug, and Coolant flange....Still no heat and tons of air getting in the coolant reservoir....So I then replaced the heater core, supply/return hoses, water pump and timing belt/components, couple cracked check valves...STILL NOT HEAT, even after hours of bleeding....it then began to run even ****tier, misfiring under high load/torque situations, just falling flat on its face spitting and sputtering but under 3k rpm it ran fine....started to determine it was the head gasket as culprit due to yellow milky oil residue in all PCV components and on the oil cap....replaced Head Gasket and Valve cover gasket etc and damn near all the PCV components....still same prob....after 2wks after new gasket it got way worse and even started overheating....and eventually got so sluggish I could barely pull out at a red light one day and had to get it towed home from Five Guys parking lot lol figured the engine had seized!!! Removed the head and found cylinder 2 and 3 severely cracked from spark plug hole to the valve seats....Purchased/installed a new remanufactured cylinder head and now it hardly idles and when you hit the gas it'll actually drop down to the point it almost shuts off.....I literally tore the timing and valve cover back apart and re-checked it 4 separate times and my marks are all DEADDD ON (first time they were a tooth off) compression test shows all cylinders @ 160psi area! SOOO, at this point I feel so stuck and don't really know where to diagnose from here, its getting very frustrating as its been sitting for 2 months now and I feel like a clueless dumbdick and I know that its probably a simple sensor somewhere causing this but Im not familiar with these cars so here I am asking for anyones advice or exp with this and will appreciate any input!!! Thank You!!!

Nasty275ss