good question i have a focus and its rpms jump all the time...i ask my mechanic what was doing it and he replied carbon build up....its very common with Ford focus. Try putting higher test gas in your vehicle
What type of battery do i need for a 2002 ford focus
how to open and change the battery of ford focus 56 reg
under the battery.
Low voltage from battery
sure connect the positive terminal directly to the booster battery and the negative battery terminal to the body
UNPLUG THE BATTERY for an hour, or so.
12 volt.
Depends on your location.
About $70 at Auto Zone.
A 100 type battery according to Pure Tyre
300 miles
The alternator is over or under charging.