Hi All

Over the last few days my V8 4.6 has started to develop a hesitation.

When I start and drive off with a cold engine for the first 20-30 seconds the engine will not rev over 1500rpm and the car stays in 1st or 2nd gear. It will rev fine when static or in neutral. After I get few pops and bangs from what sounds like the left hand side everything is fine.

I have checked the plugs, leads & all the connections I can find and the plugs look fine, can't see any arcing on the leads and all the connectors are well home and clean. The car does not seem to be using anymore fuel that usual.
Can anyone suggest what else I should be looking at?

I know a proper diagnostic is the what is needed, but my local stealer has a 2 week wait for bookings and none of the local garages have test book. Would an ODB reader provide enough info for a diagnostic or do I need faultmate or test book?

NB it is a 2001 Range Rover vogue 4.6 with LPG

Your LPG system needs tuning. I would wager that the vaporiser has got a bit tired so your not getting sufficient gas pressure. This throws out the long term trims so when you start on petrol the engine ECU reads the long term trims and sets the open loop fueling to suit. As the petrol system is OK it will supply too much fuel until things warm up and it goes closed loop.

rewmer said:

Your LPG system needs tuning. I would wager that the vaporiser has got a bit tired so your not getting sufficient gas pressure. This throws out the long term trims so when you start on petrol the engine ECU reads the long term trims and sets the open loop fueling to suit. As the petrol system is OK it will supply too much fuel until things warm up and it goes closed loop.

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Thanks, guess that means I need to get a service done on my LPG or do I just need to put a tank of petrol through to reset the trims?

The last LPG service was 6 months ago and my nearest LPG service place is 100 miles away

If you run it on petrol then when you go to gas it will just re- trim. You need to get the two in sync with a tune up. Run it on petrol for a while and then get the LPG tuned.