This reminds me of an old old story...
Little old lady gets given a Morris 1000. After a week she takes it back to the dealers complaining of rough running and rubbish fuel economy. Leaves it with them and goes for a haircut. 2 hours later she's back and the mechanic tells her he can't find anything wrong with it. He asks her to demonstrate the problem. She hops in, pulls out the choke out of the dash, and hangs her handbag on it.