Hi,

My ford focus 1.6 petrol 2006, has started to have a slight issue. When idle the whole car shudders slightly every couple of seconds and the revs are a little erratic (up and down around 100rpm).

I've read lots of forum post about similar problem - but usually much worse where the engine will occasionally stall. My issue isn't currently too bad but very irritating and I'd like to fix before it gets worse.

I've read it could be engine mounts, vacuum hose, idle control valve, etc.

Any ideas?

I have the same problem with my 1.8 petrol

Have read somewhere very recently about checking the vacuum pipes at the back of the engine, as well as spark plugs & leads

Will be doing that myself tomorrow

Its difficult to diagnose the very design of tge engine is such that the idle is set low to reduce emissions the car using lots of sensors is constantly altering the fuelling and idle to keep those emissions low too many short journeys is enough to cause the issue you describe as is old plugs incorrect plug gap a faulty lead or lack of grease on the leads to the plugs a faulty sensor even the weather can effect it start at the begining check the plugs and gaps clean up the electrodes make sure all the leads are fully locked in place they can come loose then use the dash displat readout to see what the revs do when the cars warm they may not be going up or down as much as you think note the max revs and the minimum above 700 below 800 is what youre looking for the 1.8 has the vacume pioe at the rear if the throttle body black hose with a bend in it check to see if it collapses when revved or has splits in it 1.6 its at the front look at the plastic manifold under it towards the battety thetes a hose going in with a silver disk attatched pull off the hose and pull out the pcv valve make sure its clean and refit the 1.8 has it in the same location