Discovery v8 - Exhaust backfire

[ryncharlton]

Hey

Have had my discovery running well on gas now for months , but now have a backfiring problem.

car is a 1994 3.9 injection , Its got a single point closed loop system and it runs well except at speed , sometimes on motorways want to accelorate from 60 to 70 , the car will hesitate and backfire - but not a manifold backfire -through the exhaust only when gas running though - petrol is ok

have i got a mixture problem? or something else - idle speed is also erratic - idles too low sometimes or too high , but does this on petrol aswell..

Thanks

[Active_Lad]

.... idle speed is also erratic - idles too low sometimes or too high , but does this on petrol aswell...

Any Petrol problem will be exacerbated by LPG, so you first need to sort out your Petrol issue so that she runs fine. THEN you can turn to your gas problem.