Hi all,

I'm looking for some advice - about 3 months ago I bought an Audi A6 Avant from a dealer in Hertfordshire. The car is 11 years old and has an LPG conversion and a reasonable looking service history. Indeed the car is in good nick in most respects with nothing really wrong that you wouldn't expect to find on a 11 year old car. Recently I had the cambelt changed at an Audi main dealer and their inspection turned up nothing untoward except normal wear and tear on the suspension and brakes.

There is one problem that I have yet to get rectified though - the engine misfires when running on LPG. It seems absolutely fine on petrol so I don't think there's anything wrong with the main engine components. I want the garage I bought it from to sort out and pay for the repair but I'm struggling here and I need some leverage. Here's the story so far:

I agreed up front all the work I wanted doing on the car - this included a service of the LPG system and a safety (LPGA) certificate reissuing. This was all done and the car was sent to an LPG specialist in the local area. When I test drove the car before buying it seemed to run fine (tested on both LPG and petrol).

When I took delivery of it it was virtually out of petrol and LPG - there was no LPG filling station on my route home so I filled it up with petrol and drove home running on that. The next day I got to a garage to fill up with LPG and that's when I discovered that it was misfiring on LPG.

I immediately called the garage who agreed to have it back in - they had their mechanic look at it and he couldn't find anything wrong with it. He didn't have any LPG expertise and only read out the fault codes from the main computer which show nothing wrong.

After that the garage seemed to drag their feet telling me it would probably sort itself out and could be damp or something. It hasn't. So I called the garage that did the LPG service and they took it in and were very good - didn't charge me for the investigative work. They told me that two of the LPG injectors were faulty and need replacing. Seemed to stack up - so I wrote to the garage and told them the situation - sent the letter by special delivery. They never replied although they did call the LPG service center to find out how much the repair would be which was encouraging.

But since then there has been silence. The LPG service center have failed to source the parts - every time I call I get some weak excuse about there being some delay - but what worries me is that they can't even tell me what the parts cost - seems suspicious - I would never order parts without knowing the cost. I've waited long enough now and having been advised by the LPG service center to not use the LPG mode until the fault is rectified the petrol costs are adding up.

Could someone please advise me on how to proceed? I'd like to approach a different LPG service center as there is one closer to home and a second opinion would be good - especially someone who has no vested interest in the situation. But I don't feel I should pay the bill. The other garages have had long enough to sort this out and haven't. If I have to take them to small claims court I will - I just want to make sure I do everything by the book as I've never had to do this before.

The car itself is basically sound and I want to keep it - just fed up with a key part of the car as it was sold to me not working.

Many thanks,

sparky