An AMM is an Air Mass Meter. The term the mass meter and mass airflow meterare often used interchangeably. What year is your car?

No matter what's wrong, one thing you may want to do is replace your fuel pressure regulator. If it is the same color and texture as the fuel rail to which it is attached, it's probably original, and living on borrowed time if it's not already gone bad. Your throttle switch is on the rear side of your throttle body. It senses the position of the butterfly valve in the throttle body and reports back to the ECU. The unit or its wiring may have gone screwy, or maybe not: read on...

Remember that these codes you're getting are the interpretations of a twenty year old computer (how capable was any computer you may have owned 20 years ago? I had an Apple //c) based on the input a half a dozen or sensors which may be in questionable condidtion. The codes are no substitute for good, old-fashioned diganostics. For example, I was struggling with codes which indicated bad signals from my mass airflow meter and oxygen sensor. A volvo mechanic suggested that replacing one sensor might easily make both codes go away. Fortunately, before replacing everything and anything, I tracked the problem down to a leaky air intake hose, causing the oxygen sensor to indicate to the computer that the engine was getting more air in the mixture than the AMM said it was. To top it all off, the codes I was getting should have lit the check engine light, but they didn't unless I raced the engine hard.

So, what are your actual symptoms?

-EdM.
--
'90 240DL Wagon 'Lola' -- '72 1800ES 'Galadriel'