Alternator Voltage and AFM meter failure

In my GU 2004 ZD30TDI Patrol an Air Flow Mass Meters (genuine Nissan's)fail in less then two years (aftermarket ones in 7 days-LOL). It started soon after a failed alternator was replaced in 2009. I have just replaced 4th AFM meter. Dirt, oil etc has been ruled out, they fail electronically. Does any one is having similar experience?
Apart from suspicion of poor quality of Nissan's AFM meter I also suspected the new alternator. It produces for most of the time 14.8V no load (have temp/volt meter mounted on dash) but I have noticed that it spikes while driving to 15V or little over. Is that normal voltage?

What should be a correct voltage from original Nissan alternator?

G'day Vicjak,

Mate can i ask you to head over to the introduction section please and post a Hello thread, you will get a much better result for your questions if you say G'day first ;)

There a plenty of guys on here willing to help and someone will be able to steer you right. At a guess i reckon 15v is a little high but thats a guess. is your volt meter after market reading in digital? are you getting that on both batteries? do you have 2 batteries?

If you have lead-acid batteries 13.2 -15.6 is the range from what I can recall but depending on the batteries temperature it can be doing damage. Do your batteries need topping up regularly? Could be the alternators voltage regulator,has this been replaced since 09?

You say you replaced x 4 MAF sensors , how come they didn't spray them and replace them.
Spray is available fro SCA and Jaycar

He said it wasnt due to oil and dirt but failed electronically so no point cleaning them