The first thing you need to do is to add a column for the rate the MAF voltage is changing. Since I'm a geek, I'll call this dMAFv/dt. Fill this entire column with the formula
=ABS(((V2-V1)/(T2-T1))*1000)Where ABS() is the absolute value function, T2 is the time from the current row you're working in, T1 is the time from the row before the one you're working in, V2 is the MAFv from the row you're working in, and V1 is the MAFv from the prior row. What you've just done is to calculate the rate of change of MAFv in Volts per second. The higher the rate of change, the more likely the data is to be unreliable.
What is meant by that? My log has one column of time and one row of mafv, but you are specifying for two.