When I bought my 2004 X350 last February, it had 160,000 miles on it. It had a Denso MAF sensor of unknown age installed. I bought a cheap $30.00 unit off E Bay, looks to be an aftermarket rebuilt unit. After 7 months of repairs, it seems to be running reasonably well now.. Is the Mileage unknown Denso unit a better choice to use than the cheap rebuilt unit? Do these go bad over time? The Denso unit is on the car now, I'm getting about 32 mpg highway. Any suggestions on which unit I should go with?? Thanks, Brandon

 

Just clean it with the MAF cleaner aerosol and you'll be fine.
Also, the same Denso MAF is used on many Toyotas, so you could buy a new MAF, they are pretty cheap.