1999 Pontiac Grand Prix Engine hesitates, disconnect MAF ru

A little stumped on this one, wondered if you can help. I have a 1999 Grand Prix 3.1L 132k miles. Great car. Starts right up, idles perfect but severely stumbles/hesitates when taking off. Exhaust smells rich, not great mileage (mpg). 1/4 mile later runs good enough to get where your going, but always lacks power/hesitates. Check this out - I disconnected the mass air sensor, which still looks new and recently cleaned with elec contact spray (MIL/code pops up that it's unhooked), and it idles erratically, (800-1000 rpm) but upon acceleration at any speed/gear I get all the power back, squeals both tires, and can practically drag race with it. No other codes have popped up. Recently replaced plugs, wires, cam sensor, cat conv, bank 2 O2 sensor, & filters. When I pull the spark wires individually, I'm getting almost 2 inch long sparks firing properly at any rpm with the mass air flow sensor hooked up or not. ECM seems ok, all connectors clean. Faulty MAF sensor or what?
I read your website often and value the information it provides by both the pros and the members, saving time and $ from the local repair shop. Thanks again for any help !