Q: Running rough 2002 Ford Focus

asked by on

My 2002 Ford Focus SE. with the DOHC Zetec engine runs really rough and has loss of power. After running for a good while it will clear up and run smooth again, sometime after stopping and shutting off engine and restarting it.I had Autozone put on computer and there are no codes. I recently replaced PCV valve and tubing because hose was collapsing but this did not solve issue. My car has 116000 miles. My car has an automatic transmission.

My car has 116000 miles.
My car has an automatic transmission.

Hi - rough running can be caused by a number of things: misfiring, dirty throttle body, injectors, fuel filter, idle air control valve and so on. There was a technical service bulletin from Ford for this engine which pointed to replacement of the PCV valve, but you’ve covered this. If there are no problem codes, fuel supply, a coolant temp sensor that is reporting incorrect temperatures, EGR valve that is not closing completely, or a "slow" or lazy oxygen sensor are suspect as well. I would recommend an engine inspection by a mobile, professional mechanic, such as one from YourMechanic, who will come to your location, diagnose this problem, give you an accurate assessment of damage and cost estimate for repairs.

Was this answer helpful?
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
  1. Home
  2. Questions
  3. Running rough 2002 Ford Focus

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: I installed a new radio yesterday and now my car won't start.

Hi there. The black wire behind the dash is your ground wire, which should have been connected to a bolt or screw that contacts the bare metal of the car's chassis. If this is not connected, the stereo will not...

Q: Q: My car will occasionally not start

A situation where the car does not always start can be caused by one of several mechanical issues, ranging from fuel delivery problems to ignition system components like the ignition coil or distributor. However, on vehicles more than 10 years...

Q: Car shaking and sputtering when idling and driving

The information provided leads me to believe that your Lincoln may be experiencing a lack of fuel pressure to the engine. If the fuel pump is unable to provide the specified fuel pressure to the engine properly, then symptoms like...

Related articles

P0240 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Range/Performance
P0240 code definition Turbocharger Boost Sensor B Circuit Range/Performance What the P0240 code means P0240 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects the intake boost...
How to Avoid Back Pain in a Car
If you have back problems, sitting in a car for an extended period of time can be excruciating. Even without back problems, you could experience discomfort and soreness from...
How Much Does a Mechanic Make in Vermont?
Automotive technician jobs in Vermont have an average mechanic salary of $37k, with some mechanics earning a salary of $53k.