I have a problem with my williams 1.
The engine has started cutting out and stalling especially when going over bumps.

After checking my battery connections with no sign of a problem, I tried spraying carb cleaner in to the carb and the other two small holes behind the air filter (I guess one is the potentiometer).
This fixed the problem the car was back to good as new.

However, soon afterwards I started getting the same symptoms which got worse and worse.
So I sprayed again and this time opened up the carb flap which was very black and oily on the otherside.
I cleaned the flap, and took the car for a 4 mile test drive and it was great again. But all trips since then on the same weekend the car has deteriorated to stalling and losing power again.
Has anyone any ideas of what i should do next?

desperate Nick

ps. btw I have checked my oil level and it is on the max, no sign of any lose.