Fixing all your keys
AO Silver Member
Join Date: Mar 2001
Location: United Kingdom
County: Tyne and Wear
I agree in principle to your comment on the air temp sensor being corrected by the lambda feedback. However, I have found that at sub-normal tickover speeds, the feedback is not fast/accurate enough to compensate for a originally poor mixture and the engine can still stall.
This is especially prevelant if the revs drop suddenly from high to low when you slow to a stop, its not a problem if you are changing gear as the change forces the revs back up again. If you dip the clutch and take your foot of the accelerator, an originally weak mix can let the revs drop to a point where the engine struggles to recover and the lambda feedback swings to over-fuel. If there is an air leak it fails and the engine dies.
Sounds like I`m making it up but I`ve experieced this in minute detail when dealing with my Autogas conversion. Its amazing what you can learn when you have to!
Blah, blah, blah. I can`t stop spouting today.
Give your car a quick check for air leaks, then take the car for a quick diognosis like James suggests. Its easier in the long run if you don`t know where to look yourself.