I posted a few days back re: what I thought was a failing air mass meter.
Symptoms were that the car lost power at speed and thereafter would not accelerate or maintain any engine speed greater than idle rpm. Disconnecting the air mass meter seemed to remedy the problem, restoring normal power but leaving me with a choppy, oscillating idle and horrible gas mileage. The car also reeked of gas at idle with the meter disconnected. Don Foster diagnosed a bad FPR last Friday, and the poor mileage and raw gas odor seemed to support this diagnosis.

But here's where it gets interesting....The other day, I reconnected the amm on a whim just to see what would happen. Started the car up and to my surprise it ran just fine. Perfect idle, OK power, normal gas mileage, and no more 'raw gas' odor. And it's ran just fine ever since. But I do notice that it is not as responsive as it should be, nor as it was with the meter disconnected. Power is OK, but it bogs down on hills and when I 'floor it' it doesn't respond.

Something is definitely amiss...but what??

TIA.

-=Bob=-

Another thing that can cause the "overly rich" symptoms -- sorry I didn't mention it before -- is a failed engine temperature sensor, bad wiring to it, or a bad connection in the sensor circuit. This sensor is the FI ecu sensor, a two-wire device mounted about under intake header #3. (The one-wire sensor under header #2 is for the gauge and not connected to the FI system.)

If the resistance climbs very high, as happens when a connector or connections fails, then the FI systems interprets the engine temp as stone cold, about minus a zillion degrees, and pours in the fuel to compensate.
--
Don Foster (near Cape Cod, MA)

...If your model has one. They can go haywire and tell the computer there is little or no vacuum (engine under load) which in turn calls for increased fuel mixture (injector open duration).