This Altima needs to be fixed badly. Any ideas?

[c7scayman]

This 2001 Nissan Altima SE has a 2.4 liter KA24DE 4 cylinder engine with an automatic transmission and it has a few problems. 118,000 miles now.

At 109,000 miles 1 year ago when the car was bought. It had a slight idle fluctuation, but otherwise drove great.

-Check Engine Light read “Random Multiple Misfire”

At 113,000 miles: idle got worse and car occasionally turns off at idle speeds whether in Drive, Reverse, Park, or Neutral. We tried doing a complete Tune Up.

-Sparkplugs changed with correct gap according to owner’s manual.
-Sparkplug wires changed
-Distributor Cap and Rotor Changed
-Fuel Filter Changed and I put some premium fuel in the first tank to prevent engine knock since premium fuel is less likely to combust prematurely.

At 116,000 miles:

-Oil change and oil filter and air filter changed.
-Mechanic notices top front engine mount on passenger side of engine is broken and needs to be replaced. We did not replace due to $$ issues.
-Steering noises start. When wheel is turned at any speed including a complete stop, it makes a LOUD humming/whining noise. The Noise only happened sometimes.

At 117,000 miles to current:

-Steering Noise now happens all the time and it is louder and worse. It wakes people up at night and turns heads because of the loud noise. It happens while turning both in neutral and in gear. Both at a complete stop and while driving. Possibly a pulley or power steering pump? Or maybe the bad engine mount was causing it?
-I manually raised the Engine idle speed by about 200rpm, but it did not help. The engine still turns off at idle speeds in any gear and in neutral.
-Mechanic 1 gave up and told us he did not know what the problem was and gave it back to us. He said there was no exhaust leak and that the O2 sensors were reading correctly and that there was no vacuum leak.
-Mechanic 2 only noticed that cylinder 2 has 20% less compression than the other cylinders, but he gave the car back to us free of charge because he could not find the causes of engine idle and steering noise.
-I removed each spark plug wire one at a time while the engine was running. As expected, the idle speed lowered when I removed each wire except for Cylinder 1(The cylinder closest to the driver side). When I removed the sparkplug wire, the engine seemed to run at the same speed. Possibly cylinder 1 is not working. Please Confirm.
-Transmission does not feel right. Sometimes it shifts normally. Sometimes it shifts early or late. It could be slipping. It might need a transmission oil change. I don’t think the car has ever had a trans oil change and it has over 110,000 miles now so I think it needs one.
-Check Engine Light still reads the same thing. “Random Multiple Misfires”
-When you hit gas to accelerate, the car drives smoothly except for the odd shifting and loud humming noise when you turn the wheel.

I tried many Nissan forums and two mechanics so far, but they have no idea what is wrong with it. Another guy who works on cars and myself also tried to figure it out many times, but we gave up.