My wifes car, (EF falcon station wagon dual fuel) has an odd pulsing happen when accelerating only on gas. It doesn't happen on Petrol at all, and it is much more noticeable when the engine is cold.

It isn't a really strong pulse in that it doesn't lurch the car, it just seems to lose a bit of power when it's pulsing (as if someone has removed a spark-plug completely so that that cylinder wasn't helping, but not hindering it as it would if the plug was in and it still had compression but no power)

Its very hard to describe.. it's not missing... it just pulses..

It has me wondering if it's not running lean or something, but I'm not sure how to tell one way or the other..

Does anyone know what I mean with this symptom?

regards

Frank

at $4 each it wouldn't hurt to replace the plugs just to rule it out.

what gas system is it?

I don't know that much about the gas system, but it has an APA tank and an OMVL R90 Converter... don't know what the mixer is but it looks very restrictive as it halves the intake diameter.

The plugs are not very old, but I just replaced the ones that were in there when I got it assuming they must have been the right heat range.. could it be blowing out the spark?

Plug gap needs to be 0.9mm.

To prove if its lean surge you could give the sensitivity screw a half turn out. if that improves it then you need to get the system tuned.

That converter is more then up to the job. The mixer should be about 43mm. But so long as its between 40 and 47mm it should work. If it less then 42mm i'd be looking for a new one though.