Yes. I have had it in my car over a month now and I think the filter is working ok. The RPM reading on my MPGuino is very steady. Therefore I think it counts the pulse as a one pulse.
Calibrating takes quite a long time. I started fooling with the injector delay setting. I 'd like the MPGuino to be accurate both on driving and idling. The calibration factor affects more to driving and the injector delay setting affects more at idle and low load. I think.
Right now I have about 4% error compared to fuelings, but overall I'm happy with the MPGuino. It shows reasonable values in different loads and different speeds.
For example a trip with towing a trailer at 80 km/h (50MPH) resulted 7,3 L/100km (32MPG)
And the same trip without the trailer at same speed resulted 5,8 L/100km (40.5 MPG)
Althought the filter is working ok in my case, I cannot quarantee that it works with someone elses peak and hold injectors. There can be different ways to control a peak and hold injector in different cars.