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: Fan doesn't come on unless defrost is on.

Hi there. I am assuming you are referring to the radiator cooling fan. If it works when the AC or defrost is on and not when the engine starts to warm up, then that can be a circuit issue or...

Q: My focus 2010 shuts off when i put it in reverse from park or drive. I took it to a mechanic but he didnt find any codes or issues

Stalling when the vehicle is put in gear occurs if the engine cannot accommodate the load. Among the causes of that are problems with the torque converter and/or torque converter lock up solenoid. Another possibility is an internal hydraulic leak...

Q: When accelerating from standing stop engine hesitates

I would recommend checking the mass air flow sensor as this is a commonly known part that can cause this kind of loss of power. This regulates the air intake into the fuel injection and ensures a proper air/fuel mixture....

Related articles

How Long Does a Heater Control Valve Last?
Keeping the right amount of coolant in a car is essential in keeping the engine at the right temperature. Failing to have the right amount of coolant or even bad elements...
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...
P2103 OBD-II Trouble Code: Throttle Actuator Control Motor Circuit High
P2103 means there is a fault with the throttle actuator control motor circuit, likely due to a defective electrical component or part.