Hiya,
Were you able to get your car sorted? And what was the exact problem? As I am having the same trouble, moves forward but won't reverse, just got fitted with LPG and i bought it with 101k on the Clock, had Lexus Service History upto 90k, LPG got fitted exactly at 100k, drove fine in the first few drives, Shock absorber was not as good, got it changed, paid 300 for a used pneumatic shocks absorber. And all of a sudden reversing from the garage on a slope, Engine Check Lights illuminated, drove around came back, tried reversing again but no reverse, moves forward but would not engage in reverse at all, tried everything. Please any help on what you did would be of a great help.
Cheers!
Mo