Propane injection is still big in diesels and will remain that way. Increased horsepower, increased fuel mileage and lower egt's.
SUMX162 is dead on.
power yes, fuel mileage (diesel) yes but only when you run it in conjuction and then your filling up two tanks (robbing peter to pay paul). Lower EGT's?????????? Never seen it! Its a catalyst (sp?) and it burns!
Propane is fizzing out, many people still run it but its getting fewer and far between, theres to many bad side affects from running it.