From: Fred Hardy on
I have had this problem with my taxi. It is a single point Prins. on a 2
litre ford transit engine. The problem started when a so called lpg garage
fitted a new vapouriser and replaced the stepper motor with a fixed control
valve. I drive o.k. around town but as soon as I go above 30 on the open
road it jerks slightly and switches to petrol. all the green lights go out
whilst flashing and the red light comes on. The prolem is emmision. The
Lamda sensor in the exhaust does not like the mixture of lpg in the exhaust
so it switches over to a better fuel. You might need a new O2 Lamda sensor,
or possibly the MAF sensor by the air intake is faulty, or possibly the cat
needs repaceing. I would suggest a full system analisise of petrol side
first. This will tell you if any of the petrol side is faulty. If that is ok
then the lpg is at fault. Avisit to a gas specialist for you system is