The amount of jobs I go to where its been diagnosed over the phone and on arrival find a totally different problem is amazing, sometimes if its a obvious common fault you can get it right, but mostly you cant, Last week I went out to a engine that was missing and 'only needed a injector' the problem for the misfire is below,
Yes, it didn't seem to like its original position, so jumped around a few thousand times until it embedded itself, the machine was still being used with a 'slight' misfire, thats what I found on arrival after being told it needed an injector by their foreman.
------------- Doing as little as possible for as much as possible...
I have a 2008 Outlander 2.0 and had been experiencing the same issue. I purchased the car in February from a dealer and it was supplied with 12 months Mitsubishi warranty.
The problem first occurred at Easter and then again at May Day and Whitsun bank holidays. The car was fine when not towing. I took the car back to the dealer for the problem to be fixed under warranty. They did some diagnostics and informed me that the issue was likely to be due to carbon build up, even though the car had only done 32k. Carbon build up was not covered by the warranty and I was looking at a very large bill to replace the turbo. The ECU was recording an overboost fault and putting the car into limp mode. I did a lot of research on the Internet and discovered that carbon build up was a very common issue in the VW units and there are even some chemical products on the market to clean it up.
I wasn't too happy about paying for a turbo as I had only had the car for less than 2 months when it first went wrong and ended up referring the issue to Mitsubishi customer services. To cut a very long story short further diagnostics were then completed and in July they discovered a software update for the ECU which addresses an overboost fault on the turbo (this is what I was told by the dealer). They applied the update at the end of July. Since then I have towed the caravan for over 600 miles using 2 of the routes that the car had failed on previously without any issues at all.
In all of my research into this issue I had only found the same possible causes as already listed in this thread. If you have not taken the car to a dealer yet I would book it in for some diagnostics ask them to check that your ECU is running the latest software.