Good Evening Gentlemen,

Got an occasional dip in RPM at idle:

- There are no codes
- Intake pressure is constant 705-710, no leaks
- NOT caps and rotors issue.
- No ETA issues
- MAF voltage is 1.5-1.6V at idle, Air meter reads 26-27KG/M BUT occasionally goes to ZERO! at the same time the RPM dip occurs.
- ON/OFF ratio is 50% with ignition on, 19-25% at idle when this occurs. (value suggests injector/s with open circuit, though injectors are fine)
- O2 sensor fluctuates between 135-750 approx.

Now I have done all the MAF tests, it is responding and functioning perfectly except for this occasional zero reading or possible grounding:

- Burn-off function, MAF filament light ups.
- Blow air at the filament, engine switches off.
- Disconnect MAF cable, LH switches to set value.
- MAF intake and voltage responds to RPM increase.

It drive absolutely fine, just noticed this after the winter.
Any suggestions? I don't want to change a good MAF as its really clean! could it still be the MAF or something else?