2001 Focus. Car is jerking when brake

RB1234

MEMBER
2001 ALL OTHER MAKES ALL OTHER MODELS

Hello:

I had recently gotten a short to my fuel system repaired by my dealer. Now when the cars is idling, it makes this jerking almost like it wants to shut off, but it doesn't.I have 77,000 miles on it and I have to get the transmission cleaned, do you think this could be it, or should I take it back to the dealer?

Thanks for your help!

1 Reply

MIKEYBDMAN

MECHANIC
623 POSTS

That almost sounds like you have a vacuum leak. IT could be fuel related, but it may be as simple as a vacuum hose has broken or become disconnected.
I dont think the transmission will cause the engine to run bad at idle.
In some of the older models, the transmissions had a modulation valve that used vacuum from the intake to modulate the shifting of the trans. If that valve went bad, it could suck transmission fluid into the intake. This usually makes it run bad, and the hose will swell and come off making it really run bad. I dont think your has this valve, but the symptoms are simular.