Help w/ 2000 Maxima...

Hi guys, I'm posting for my cousins 2000 Maxima GXE. For a couple of months now, it has been given some problems. The first problem is that when it's in park or neutral, it'll idle for a minute then begin to stumble where it then dies. He has to keep it in drive just so it stays running. Another problem he's encountering is when he's driving at cruising speed and decides to give it gas, the rpms would go to a lil over 3k and stay there, where you can actually hear the car start to misfire. And just recently, his maxima started to stall out on him while driving and won't start until probably the 3rd or 4th try.
Throughout the entire ordeal, he has had a CEL. We took it to autozone and when they pulled it all it said was problem in one bank and gave possible causes as ignition, o2 sensor, MAF sensor and a couple of others (really wasn't helpful). Can anyone be so kind as to shine some light on this. I'm thinking something to do with the coil packs, but then again I'm not no expert. Any advice would be greatly appreciated. Thanks in advance.

... possible causes as ignition, o2 sensor, MAF sensor and a couple of others (really wasn't helpful). Can anyone be so kind as to shine some light on this. I'm thinking something to do with the coil packs, but then again I'm not no expert. Any advice would be greatly appreciated. Thanks in advance.

Service history, mileage?

Bad MAF is one typical issue in 2k maxima. When nostart is acute, unplug MAF: If it starts now, then points to faulty MAF [2k rpm ceiling]... Try to find a spare MAF from JY for tst purposes; the self diag doesnt help too much.

Plugs have to be changed every 60k. Coilpacks start to die after 100k, only replacement help$.

RPM jump points to slipping tranny. Feels then like drivetrain is disconnected.

Other possibilities, read linky pages 10 & 14 below...

I'm no expert but with all the symptoms you have listed here theres no way an expert from this site or any other would be able to help you. You have to get it diagnosed, it seems you have multiple problems. Hook it up to a code reader and go from there.