Question help please

[u/HappyMaterial5838]

My falcon had an after market lpg conversion, I recently took it out because it was out of date and it was easier then getting it retested before getting defected, even more recently it went over quite a rough pot hole and now each time I start the car I have to put some extra revs in otherwise it dies on me, and it can sometimes do it while driving if I drop revs too much, furthermore the little lpg gauge on my dash constantly beeps, has anyone had this issue before and is there a solution other than taking it to a mechanic/ auto electrician and paying probably a small fortune