VT struggles/backfiring on lpg at revs, what could my problem be?

[JAKE-26]

Hey all.
I have a vt with dual fuel(exec, auto). When i run it on gas it runs fine and i dont really see much of a performance drop, but when i rev up to about 2300-2600 rpm it always sort of bumps/struggles/backfires but when its not in that rpm range its fine?
Just wondering if anyone can suggest what the problem would be? could it be the computer or something?
it runs fine on petrol, and anywhere out of that rev range on gas.

thanks for any help!

 

[jetboy]

Plugs , leads and air filter , any of these or a combination of them will cause ur problem , an yes it will run fine on fuel but not on gas if any or all are stuffed . coil pack could also cause a drama
start with thy cheapest an work ur way up if u dont know how to test these items

 

[JAKE-26]

I recently put a lukey air filter in but its always done it so i can rule that out.
Plugs and leads could be a good start to tell the mechanic next service. really got no idea how to test any of that lol
cheers!

 

[HamaTime™]

In that specific rev range on gas it won't be the computer (that is I'm assuming you have a carby styled air mixer gas system, rather than direct injection which is ECU controlled).

Check your DFI module, that causes backfiring, though if the problem is rev range specific and fuel (LPG) specific, then the problem will most likely lie with the gas system.

First step is to check leads, coils, DFI, sparks etc...but I'd take it to a LPG workshop to be sure. LPG is prone to problems when all is not perfect, and hard to fix.

 

[JAKE-26]

Yeah dad (previous owner) told me that the lpg mechanic has no idea where the problem lies but said something about the ecu. I was also told it is a direct injection system so i guess the mechanic could be correct, i just find it weird that it always struggles at the exact rev mark. Whats a DFI also?

It's not the worst problem in the world though. sometimes i just drive it on petrol coz i would like to get above 2.5k smoothly