How can I fix my renault laguna?

Hi,
I am afraid I don't know the solution to this yet. But I will share with you what I know.
I am having exactly the same problem. The trouble is as you said when you leave it alone for half an hour it goes away! And it doesn't even store a fault code for the technicians to see. Once when I had this problem I called the AA and they connected their computer and found a fault code with the description P0120 'Throttle/pedal position senor switch A circuit'
I took it to the garage but they couldn't find any fault with it so I had to take a day off and drive the car all day to get that problem again. Then I showed it to them and they charged about 300 pounds and told me it was fixed.(they changed the throttle body) But I had the problem the very next day! So I am going to take it back to them. I will let you know if I find anything more.

So far I have noticed the following things.

It only happens after you have driven the car for about at least half an hour.
It always happens when you are on a low gear (first second or reverse)

sam
December 2007