Propane Gas Backfire

This normally does not have anything to do with the fact that this is an LPG vehicle unless you have a leak in the intake and this gas is igniting in the intake.

However, the fact that you only have this at higher gears means we have a lighter load on the engine, I suspect this is just a poor ignition issue or possibly timing issue.

Here is a video that will get us started.

https://youtu.be/HiI_eeFg-2A

I am attaching the info below on how to change the timing belt. If it were me and you have not changed the belt, then it is past due, and I would suggest doing this and setting the timing correctly.

Please run through this and let us know what you find. Thanks