The Cleaning of the MAF is what did it. On my 1994 Mustang Gt it was a common problem for those cars to ping with little timing advancement and 93 octane fuel.
I would always pull the sensor for the MAF out of the housing and clean it with a cue tip and some rubbing alchohol.
Remember..... All you guys running the K&N type filters are making this even more of an issue. Because those filters are "charged" with the oily substance.....It will attract more dirt to these sensors. Therefore they will need to be maintained more often.
When I cleaned the MAF on my mustang, not only did it clear up the pinging but it also picked up over half a second in the quarter mile. No joking. This was an older car with more miles but....Just an example of how bad it screwed up the a/f mixture.
