Is there only a difference when the engine is warm? As opposed to, say, when the engine starts?

Like, if you've been driving for 10 minutes and then you stop for 5 minutes and then restart your car, it'll run smoothly?

 

The plug-in system analyzer will tell you 'closed loop low temp fault' or something like that. Till the engine warms up, it is in the closed mode. Warm engine, OPEN loop. If plugs are okay and gapped properly, and fuel filter is new(er), check coolant level/quality.

Or take in for service.

 

Exactly. If I have been driving around and then restart the car while it is warm, then it is as smooth as it used to be.

 

I had a similar problem w/ the cold start thing and mine turned out to be the O2 sensor (the one I had just replaced less than a yr ago ). For some reason it wasn't reading right until it got good and warm then it would run smooth as silk. Try unplugging the primary O2 (the one before the cat) and start it when it's cold. If it runs smooth, problem solved.

 

I had very similar problem with my SVT, noticed it when tank was nearly empty on one particular fuel load. A combination of a full tank of quality fuel (I'd purchased the previous tank at a thrifty station by necessity) and a change of spark plugs provided the cure.

 

Lots of things to check. Thanks everyone.

 

The noise, and what these guys are saying, seem like 2 different things.

The poor running could be what people have been saying.

The grinding? Thats weird. It doesn't grind when it gets warm when you hit a bump?

 

i replaced my driver side(transmission) motor mount and rear motor mount, much of my engine noise has stopped(need to replace passenger side one still).
that noise includes minor grinding/rubbing sound when going over bumps.

motor mounts were about a 4 on a 10 scale of dificulty. mostly need a good arm or prybar for those old mount bolts.

 

Its not exactly a grind so much as a harsh rubbing sound almost like a bad bushing in the front suspension somewhere. Its really hard to describe. It does happen after the car has warmed up but its not nearly as noticeable. When it is cold it feels like a strong vibration more than a grind I suppose. I need some daylight after work to climb under and check things out, but now of course daylight savings is over. Maybe tomorrow.

 

Don't suppose you've made any progress on finding a cause? My '04 ZTW is showing exactly the same symptoms. They developed at almost exactly the same time too. Uncanny.

 

Sorry, I should have added I don't have the grinding noise - just the engine roughness. But exactly the same, it happens when cold. If the car's been sitting in the sun it's quiet. It I start it in the morning I get five minutes of rough engine noises.

 

I've had this same issue here recently. My car has been in the shop for two weeks now. I should get it back tomorrow. Luckily everything is covered under the extended warranty.

I had several failures at one time which seem to have contributed the rough cold weather starting:

1. Ignition Coil
2. Fuel Injectors
3. Throttle Body
4. Motor Mounts

2003 Ford Focus ZTS 2.0 Zetec 72K miles.

 

the noise over bump maybe suspension related ball joints would be my guess

end the cold start issue sounds like lean condition to much air or not enough fuel that thats has a "miss or rough" result so check or change fuel filter and if not check for any vacuum leaks

 

So, much strangeness.

A day or so after posting, I was parked at a supermarket. Climbed in and went to start the car. Once click and all the electrics went.

The battery was dead. Even ten minutes with jumper cables wouldn't start the car.

After a new battery was installed, all the cold start roughness was gone and has remained gone for several days.

So, can anyone suggest why a dying battery would cause the car to perform roughly for five to ten minutes when starting from cold?

 

no but a poor connection on the ground cable certainly could

 

Thomas, thanks. That may well have been the problem then - there was significant corrosion around both battery terminals.

 

So, my problem returned a few days after the new battery was installed. The terminals are clean, so I think that's eliminated as a cause.

The car is an 04 2.3l ZTW with manual transmission.

Since mid-October I've been experiencing this rough engine noise when starting from cold. It seems to go away after the car has been driven for about 20 minutes.

It appears while accelerating, particularly in the lower gears as revs increase. It's not constant through the revs though, so the engine will sound rough then a fraction of a second sounding normal then rough again.

I'd describe the noise as sounding almost like a motorbike engine. The car goes from quiet and smooth to loud, rough and noisy.

It is particularly prevalent when making a right hand turn - i.e. a sharp 90 degree turn while accelerating away. For example if I turn right on red onto a fast road.

The car went in to the shop who replaced the idler kit and serpentine belt. That's achieved nothing other than lowering by bank balance by several hundred dollars.

Would anyone have any other suggestions? Why would the noise go away for days after a new battery is installed then return? Disconnecting the battery for an afternoon then reconnecting did not make it go away a second time. There's no check engine light on.

I really know little about cars, and fear spending hundreds more as the shop takes stabs in the dark while not getting this resolved.

Thanks!

 

Thought everyone might like an update of my rough running problem. Just finished replacing the pass side motor mount, and it was beyond shot. Started the car up with the new mount and its is smooth as a brand new car. No rough running when cold no funny clunks going around curves or hitting bumps. I thought there might have been something loose in the suspension, but with the new mount, it feels like a brand new car. Only took about an hour to replace with an extra set of hands helping out. Thanks for everyone's suggestions and help!

 

I had a very similar issue with a SPI sedan i had and to my amazement when i replaced the motor mounts as just one last shot in the dark it fixed it. Surprised the hell out of me. The going over bumps thing is what realy confused me about mine.

 

I've always thought it was normal but my 2.0L Zetec always ran a little rough on cold starts until the RPMs fell below 1000. I notice this happens a lot less when I use synthetic oil. I think what you might be experiencing is a lack of oil flow through the engine on cold starts which causes a rough(er) feeling. Try using a thinner and better quality oil next time, I usually use the recommended 5w20 but I notice a difference on engine idle when using synthetic or conventional oil.

I would also double check all of your engine mounts that will help a bit with the vibrations.

 

That makes sense about the oil as mine now runs a little rough on cold starts and I ended up switching to 5w30 Mobil 1 before this started happening. (meant to pick up 5w20 but failed). Next time my oil change comes up I'll have to switch to 5w20 again.

 

So I've been experiencing something VEEEEERY similar to the OP for a while now. Is there any way to check to see if the mounts are shot without removing them? If not, once I have them out (one at a time, of course), what am I looking for?

rough idle on cold start up, then fine after 10-20 minutes of driving. odd grinding/rasping noise when I hit bumps or dips as well as a small blip of that same noise when shifting.

Its a 2002 SE w/ zetec and 5sp, 130k miles.

 

The cover on the passenger mount comes off to see if it is domed or collapsed, the trans mount gets hard and may even show cracks if it's old enough, the dog bone should be replaced fairly frequently anyway. [Side note: You can substitute a poly insert in the large side to help control wheel hop while still keeping vibrations at bay.]