When it boosted in 2nd was it normal boost or higher/more savage than normal?
I would imagine as the car is idling ok and unplugging the MAF has made no difference that the MAF may not be the issue (but stranger things have happened).
Have a look under your dash and see if you can see a pair of black single pin connectors right next to a set of green 2 pin connectors, they should be directly under the dash roughly in line with the steering wheel. If they are there plug the 2 black single pin connectors together then turn your ignition on (dash lights on engine off) you should see the check engine light flash, a slow flash = x10 a fast flash = x1 so 2 slow and 6 fast = 26 and so on, there may be more than one code if so there will be a pause between codes, the series of codes displayed will repeat in a loop so dont worry if you miss it you will have plenty of time to get it as it repeats. When you are done switch off the ignition then unplug the black connectors.
Cheers Iain