I have a couple of issues which I hope are all related.

The car is a petrol Ford Focus 2000 1.8. Seems to be listed as LX, but the engine is Zetec.

When stationary, the idle is quite jumpy, and the car seems to rattle a little - likely because the idle is too low. It's improved slightly over the past couple of days (the pin now sticks around the 750RPM mark), but it's still not perfect.

Also, when driving, if I come up to a red light, disengage the clutch and brake, the revs go up to about 2000RPM, and then down to about 600, and are jumpy again. Twice today in this scenario, the car stalled and was unable to keep idling. When the idle is low, the dashboard lights also flicker a little.

There's also a fair amount of white smoke from the exhaust. I've only driven about 8 miles in one go since these problems have occured, and the outside temp has been no more than 4C, so it's possible that it's just steam?

The engine management light is on. I've checked the dashboard error codes, and it comes back with the low battery voltage error. I haven't yet had chance to check out the true engine error codes.

Any idea what the issue(s) could be here? :)

Edit: I've just had the battery tested and that came back perfectly fine. The tester was unable to read the engine management codes, but he was confident that there's a misfire which is causing the symptoms I'm having, but exactly what is causing the misfire would come up when reading the codes.

Edit 2: Okay, I've had the codes read and it came up with P0171 (System Too Lean(Bank 1)). I also had the coolant checked and they said that there wasn't any in there...this doesn't sound good...any advice at this point? :)

Final Edit: Well...the rough idle, stalling and P0171 problem has been fixed! There was a small vacuum leak which was tapped up. BUT, they also did a block test and pressure test at the same time. The pressure test came up fine, but the block test confirmed that there's a small leak from the head gasket. Quoted around £700 to fix, the cars value is around...oh...£700.

Thanks for your suggestions, all. If you're reading this with similar symptoms, I hope it's not the same result!

  • The mileage is 110,000, and yeah - it's a manual. Hopefully will get the codes read tomorrow and see where we're at! Thank you.
    – edparry
    Dec 12, 2012 at 19:37
  • Yeah, it's 110k miles. Updated the question - the error code was P0171
    – edparry
    Dec 13, 2012 at 14:04
  • @MarkJohnson I don't, unfortunately. They did say, but it's escaped me now.
    – edparry
    Dec 14, 2012 at 12:28

3 Answers 3


The factory plugs should be good for 100,000 miles / 160,000 km or so. They're ridiculously easy to change on a Zetec. If you can handle a screwdriver and a socket wrench, you can check / change them yourself. They're easily accessible from the top of the engine through holes in the valve cover. The plug wires are also easy to inspect, just keep track of which connector they should plug into on the coil pack and number them yourself if they don't have a number molded into them.

It's probably worth checking the idle air control valve. It should be on the driver side of the intake manifold, under the throttle body. Depending on what's in the way, it might be easier to access from under the vehicle.

The timing belt can cause all sorts of trouble, it's due before 100,000 miles (it will actually fail around that point if it's not been changed) but I don't remember the specific number. If you pull a code for the cam position sensor, I'd actually suspect the timing belt first unless it's nowhere near needing replacement.

As for the white smoke, could be steam, or you could be burning coolant. Keep an eye on your coolant levels. If you're loosing coolant, you're burning it or leaking it.

Other than that, if your MAF sensor has never been cleaned, it might be worth picking up a can of cleaner specifically for MAF sensors. It's in the intake air path on the driver side, between the air box near the battery and the intake manifold.

That's all the generic Zetec tune up advice I've got. Report back with your mileage and have those codes pulled.


I've seen that P0171 before on a Zetec. I'd guess that vacuum leak was on the hose going into the valve cover. As for the coolant leak, that sucks, but before you write the vehicle off, consider that the engine has been known to run for 250,000 miles without a rebuild (well, the 2.0L on the CDW27/Contour/Mystique/Mondeo anyway). Also, check out this thread. The owner has a 1.8L Zetec in a Ford Escort with a shop diagnosed head gasket leak. He tore the motor apart himself and couldn't find it. You might have a very small leak. It might be worth driving the vehicle for a while and checking the coolant loss rate (keep an eye on the level in the overflow tank in the engine bay, note the max and min markers). You might not have burned all the missing coolant, the thermostat housing (plastic box on the front driver side of the engine with a hose going into it) is a known weak point for leaks. If you're adding coolant, make sure to use the correct (50/50) mix of coolant and water. Given your year, you should have conventional green antifreeze.

  • Thanks for your update, Mark. A second garage took a look, and didn't feel that it was too much of a concern at this point. The only real symptom of head gasket so far is the white smoke from the exhaust, and after driving for half an hour, that disappeared too. If anything, there could be a slight leak in the gasket, that closes itself as the temperature rises? Still, I'm keeping an eye on the coolant levels for a while, and we'll go from there. Thank you again!
    – edparry
    Dec 17, 2012 at 10:39
  • I might interject here that antifreeze color no longer means anything... there are five different mutually-incompatible "chemistries" of common antifreeze, and none are color-specific; there is no industry standization of color. Select ONE antifreeze by manufacturer and type, and never blend anything else with it. If you need to top off but can't get that specific antifreeze for some reason, drain & flush & replace it all. Anything else is begging for trouble. Some incompatible mixtures can totally dissolve a gasket as quickly as overnight. Aug 6, 2014 at 21:33

Could be many things, but I'd start with what it gives you. Have the alternator checked. It may not be putting out enough to keep the car powered at idle, slowly draining the battery, causing the idle to lower do to low sparking ability.

Just a wild stab in the dark, probably wrong. It could also be other problems that didn't trigger a code causing a low idle, which causes low alternator output, which may have then caused the code.

  • Thanks for your response. I should maybe add that with the aircon/heaters/radio/lights all on, the idling is marginally more stable. If it were the alternator, would this be the case? Or would it make it worse with it requiring more power?
    – edparry
    Dec 12, 2012 at 12:27
  • Those should open up auxiliary air valves on the intake, allowing the car to idle-up. This would also increase the load on the alternator. So, sounds like it might not be the alternator as the root cause.
    – Nick
    Dec 12, 2012 at 14:13

carbon build-up (Carbon Soot) in your system will also cause white smoke as the carbon attempts to burn away. Maybe you should check your easier possibilities first. MAFS- Mas Air Flow Sensor, EGR- Electronic Gas Re-circulator, Throttle Position Sensor, O 2 Sensor, and you may want to clean out your Throttle body unit. Videos on these subjects are available on Youtube.

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