I have an 00 max that over the past few months has developed this problem. It usually happens in the first 5-10 minutes of running the car when it is cold first thing in the morning. It knocks, pings and won't go much over 30-40 mph. I've taken it to nissan and they say because the car hasn't shown any codes, they don't know what is wrong. They said it wasn't the coil pack TSB. I paid $300 for a new MAF that didn't fix the problem. It is now getting worse and I have almost been hit because I couldn't accelerate getting on the interstate. Nissan just said maybe the part that is going bad will just break and then we'll know what to fix. I hope someone out there can offer some insight.

 

When you are trying to accelerate beyond 40 mph, what do you see on the tachometer?
If the engine is responding, but the car does not accelerate, I think there must be a disconnect somewhere in your transmission path.