3.9 V8i RUNNING ROUGH ON PETROL

Hi, i've got a duelfuel disco which i run about 99% of the time on LPG, today when i ran out of gas and switched to petrol jesus christ it was lumpy! It revs to about 3000RPM fine and then then just loses power and just seems to run really rough, its running sweet on LPG still. Ive put a bottle of injector cleaner fluid in and took it for a little run but its made little if any improvement, any ideas?

anyone?

I take it it must be a problem with the petrol fuel delivery system as otherwise it would run rought on both fuels right? I ran VERY low on petrol recently and was wondering could i have sucked up all the **** in the bottom of the tank? My other "theories" are either the fuel pump or dirty injectors (im not too savvy with the workings of the engine when running on petrol) And a friend also mentioned that maybe its feeding some LPG into the mixture and making it too rich - funnily enough it does feel like its running rich and as i ease off the accelerator the performance seems to pick up a little. Please help

Depends on which ECU you have, and whether or not it has the ability to change its settings according to circumstances.

I'd suggest taking the battery off line for 30 minutes, starting up on petrol and running it on petrol for a while to see if the ECU takes that and runs with it.

We run on both on a daily basis, but tend to be slanted to gas on long trips.

Peter