My son drives a 1999 Escort ZX2 with the L4 2.0 liter engine. He was
complaining that the car doesn't
have as much power that it used to and that it idles rough. I connected my
scan tool to check things out ( I'm new at this and far from an expert) and
noticed that the mass air flow sensor was 2.7 volts at idle. The specs are
..6-.9 volts.
The calculated engine load was 59.2 % at idle. The long term fuel trim
showed 2.3 %. There were no trouble codes set. Is this enough evidence to
replace the MAF sensor? I hear they aren't cheap so I need a second opinion.
Thanks so much for any help.

Dennis