another way to recoup some performance from your maf is to apply electrical contact grease to the connector that relays the signals to the ecu.
the grease is quite expensive as it is a special grease that helps conduct electricity and prevent corrosion of the terminals. simply pull the plug off and liberally apply it to both male and female connectors (gold plated ones) and put the plug back in.
this should cure any flatspots you have throught the rev range which were caused by a dodgy connection due to corrosion of the terminals or build up of dirt/moisture over time.
grease can be bought from places like RS or maplins.
it worked wonders on my V5!
thats ?4.99 please [

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