A failing E36 MAF (the hot-film air-mass sensor) shows as hesitation and flat spots, a rough or hunting idle, sluggish power, stalling, poor economy and sometimes limp mode.
The classic "it runs better unplugged" test is directionally true but needs care. With the sensor unplugged the DME falls back to a default rpm/throttle map:
- Runs the same or clearly better unplugged → the MAF is feeding bad (usually low or erratic) data
- A healthy car runs slightly worse unplugged, because it loses closed-loop trim
So smoother or snappier unplugged implicates the MAF; no-change or worse points away from it. Treat it as a quick indicator, not proof — confirm with live data or a known-good sensor.