For about 2 days now, the car has a really rough idle while in drive, and will fluctuate all over the band from 500 rpm to 1100 rpm in just 1 or two seconds. It almost seems like its missing. It goes away above about 2500 rpm, but there is a huge power loss. Any suggestions?

 

Could be a vaccuum leak. There is a canister below the battery, I had a line break there receantly and will have to replace the entire canister, I just sealed the line off for now. Otherwise I would say to check your distributor cap and rotory button, plugs and wires to see if they need replaced.

 

I had similar problems on a 91 Maxima. Replaced the dist cap, dist rotor, plugs...Smoothed way out, but didn't touch the stumbling problem. Mine was not just at idle but all the way through the power band. Really noticeable though in drive at idle.

The real solution was the O2 sensor. You may want to read the "Missing all the way through the band" thread...It may help.