Engine "shuddering" on idle

Goreygal

Hello All

Hoping for some help.

Have a 00 Reg Mark 1 Ford Focus 1.4 Petrol. It's serviced every year and at last service had belts replaced etc.

A few months ago I noticed the engine is "shuddering" when idle at traffic in a kind of circular pattern if that makes sense? I can't seem to find a pattern to it (hot or cold weather, long or short distances). I took it to my mechanic and he couldn't find any loose engine mounts etc and the computer diagnostic found no engine faults. The other night I was idling in a car park waiting to pull out into a line of traffic after a concert and I noticed the shuddering was noticeably visible on the rev counter... it was pulsing with every shudder up to just under the 1 marking.

I'd really like to get this sorted but am a loss as my mechanic can't find any obvious fault. Any suggestions (and yes..am considering a new mechanic for a second opinion).

Gg

Avns1s

Coil packs, dirty throttle body and faulty throttle position sensor are issues I would be checking as well as spark plug leads on a car that age.

What mileage as a matter of interest?

mickdw

It could be anything but no harm to rule out a leaking brake vacuum pipe. I wa driving around a few years ago with a slight miss at idle. Turns out it was a cracked pipe serving the brake servo. Luckily it failed at 20 mph one morning and not on the motorway a few minutes later. Very little brake effort when it failed.

Goreygal

Avns1s wrote: »

Coil packs, dirty throttle body and faulty throttle position sensor are issues I would be checking as well as spark plug leads on a car that age.

What mileage as a matter of interest?

Cheers... and mileage is only 64K

Goreygal

mickdw wrote: »

It could be anything but no harm to rule out a leaking brake vacuum pipe. I wa driving around a few years ago with a slight miss at idle. Turns out it was a cracked pipe serving the brake servo. Luckily it failed at 20 mph one morning and not on the motorway a few minutes later. Very little brake effort when it failed.

All my brake and clutch lines were checked a few months ago as I had major problems with it stalling at low revs one weekend; turns out I had a hairline crack in one of the cables. The shuddering pre-dated that and wasn't resolved by it

Del2005

Avns1s wrote: »

Coil packs, dirty throttle body and faulty throttle position sensor are issues I would be checking as well as spark plug leads on a car that age.

+1

Start with the throttle bodies 1st, only cost a bottle of WD40 and google to find out where to clean.

EPM

My MK 1.5 focus always did that. Slight vibration is normal...according to ford...

pred racer

I've had this on a couple of small petrol cars (not focus, a micro and a colt iirc) both times it was a vacuum line that split.

Antikythera

mickdw wrote: »

It could be anything but no harm to rule out a leaking brake vacuum pipe.

Goreygal wrote: »

All my brake and clutch lines were checked a few months ago as I had major problems with it stalling at low revs one weekend; turns out I had a hairline crack in one of the cables. The shuddering pre-dated that and wasn't resolved by it

There is usually a short pipe running from the inlet manifold to the brake servo. This might have been missed on your inspection. mick talks sense, have it checked.

Goreygal

Thanks for all the suggestions folks

Will write a list and take it down to the mechanic to discuss.

Goreygal

EPM wrote: »

My MK 1.5 focus always did that. Slight vibration is normal...according to ford...

This is more than a slight vibration; it's a very noticeable shake... and has only been present a few months so don't think it's the same thing...thanks anyway.

GTDolanator

engine/g-box mount,its worth a look tbh

dylbert

could also be the idle control valve

AzureAuto

Someone told me once that Ford issued a recall for software updates for the metering of fuel at idle speed. I cleaned my own out throttle plate out with a can of brake cleaner (against the rules, so say Ford) and it improved the idle shake for a little while.

Nissan doctor

Del2005 wrote: »

+1

Start with the throttle bodies 1st, only cost a bottle of WD40 and google to find out where to clean.

WD40 into the throttle body....good lad:eek:

Carb cleaner is what should be used to clean a throttle body.

kona

mickdw wrote: »

It could be anything but no harm to rule out a leaking brake vacuum pipe. I wa driving around a few years ago with a slight miss at idle. Turns out it was a cracked pipe serving the brake servo. Luckily it failed at 20 mph one morning and not on the motorway a few minutes later. Very little brake effort when it failed.

Servos are brake assist, they dont affect the efficiency of your brakes, running w/o a servo just means you have to push harder on the pedal.

Although I can see where it would give you a fright when the force you are used to applying doesnt have an effect.

Perhaps theres a issue with the balancing on the rotating masses, was the clutch replaced recently?

-Chris-

Goreygal wrote: »

I took it to my mechanic and he couldn't find any loose engine mounts etc and the computer diagnostic found no engine faults.

If your mechanic's first port of call was to check for loose engine mounts and clear the fault codes, I'd be looking for another mechanic if I were you.

mickdw

kona wrote: »

Servos are brake assist, they dont affect the efficiency of your brakes, running w/o a servo just means you have to push harder on the pedal.

Although I can see where it would give you a fright when the force you are used to applying doesnt have an effect.

Im aware that its only assistance however it would mean running into the back of someone at motorway speed without a doubt as nearly impossible to get enough pressure onto the pedal without the assistance and also there would be the critical delay in figuring out that additional pressure is what is needed.

kona

mickdw wrote: »

Im aware that its only assistance however it would mean running into the back of someone at motorway speed without a doubt as nearly impossible to get enough pressure onto the pedal without the assistance and also there would be the critical delay in figuring out that additional pressure is what is needed.

Unless you have sissy legs, you would well get enough pressure , provided your brakes are decent. But as you said , It would take a second to figure that you need more pressure, a second that in the unlikely event of needing to stop dead ASAP , isnt really one you can afford to lose.

creedp

mickdw wrote: »

Im aware that its only assistance however it would mean running into the back of someone at motorway speed without a doubt as nearly impossible to get enough pressure onto the pedal without the assistance and also there would be the critical delay in figuring out that additional pressure is what is needed.

I'll second that. Recently I let my car roll down a rather steep driveway without starting it simply to move it out of the way and I was nearly standing on the brake pedal to get it to stop and that was only at 10mph. I'd shudder to think how long it would have taken to bring it to a stop at motorway speed

mickdw

kona wrote: »

Unless you have sissy legs, you would well get enough pressure , provided your brakes are decent. But as you said , It would take a second to figure that you need more pressure, a second that in the unlikely event of needing to stop dead ASAP , isnt really one you can afford to lose.

I certainly dont have sissy legs.

kona

mickdw wrote: »

I certainly dont have sissy legs.

Then yall be fine

vincenzolorenzo

OP when you say shuddering, do you mean it feels like the engine is loose and is rocking under the bonnet or is the engine 'hunting', by which i mean it behaves as if you were constantly blipping the throttle between 800 and 1500 rpm?

carveone

vincenzolorenzo wrote: »

OP when you say shuddering, do you mean it feels like the engine is loose and is rocking under the bonnet or is the engine 'hunting', by which i mean it behaves as if you were constantly blipping the throttle between 800 and 1500 rpm?

As if the engine management is going "uh oh" and boosting throttle to stop the engine cutting out? You could also see if your apparant power has dropped off - by which I mean sluggish acceleration. I'd think it's all about fuel flow then.

Could be the injectors then which are easy enough to test with a meter - check that all 4 have the same resistance (something like 15 ohms, but it varies with car type). Plugs and gaps can be checked, fuel filter is unlikely these days. Fuel pump and HT leads would be next. Lots of stuff to check

Also: check that the pipes to the PCV valve aren't split - look at the inlet manifold (black plastic yoke on front of engine) you will see 2 rubber pipes coming off the engine. These 2 pipes join and connect to the PCV valve. I'm just throwing things that aren't ridiculously hard to check.

Third_Echelon

Goreygal wrote: »

Hello All

Hoping for some help.

Have a 00 Reg Mark 1 Ford Focus 1.4 Petrol. It's serviced every year and at last service had belts replaced etc.

A few months ago I noticed the engine is "shuddering" when idle at traffic in a kind of circular pattern if that makes sense? I can't seem to find a pattern to it (hot or cold weather, long or short distances). I took it to my mechanic and he couldn't find any loose engine mounts etc and the computer diagnostic found no engine faults. The other night I was idling in a car park waiting to pull out into a line of traffic after a concert and I noticed the shuddering was noticeably visible on the rev counter... it was pulsing with every shudder up to just under the 1 marking.

I'd really like to get this sorted but am a loss as my mechanic can't find any obvious fault. Any suggestions (and yes..am considering a new mechanic for a second opinion).

Gg

I have a 2006, Mark 2 focus and I've noticed the same thing happening recently to mine as well. Sitting idle, it will blip like you mentioned.

I've actually had the car splutter/chug on me recently as well in low revs and low gears.... like dirty petrol or something like that?