The MAF sensor is delicate and the exact position in the housing is critical, many people have damaged them. Then again yours has seen a lot of use, they get slow to respond sometimes and cause wierd problems.
Cleaning it may have uncovered annother problem and its about time you cleaned the EGR, TB, intake, IAC, and checked the PCV system if you have not done so.


"Those who cannot remember the past are condemned to repeat it" -George Santayana