Hi,

My Ford Focus MK1 1.4 Zetec (2003) has been rhythmically vibrating when idling – about every second or so (see video https://imgur.com/a/SYVet3z). Started after some maintenance work washing the engine, replacing belts, water pump, fixing power steering leak and replacing power steering pump, replacing coolant. After that idle was rough but is mostly stable around 600-700rpm now after resetting the ECU.

However, I'm now getting these rhythmic vibrations when idling warm. Otherwise everything seems fine.

Any ideas what could be wrong here and how I could address?

Are all the engine mounts in good condition ?

1 hour ago, unofix said:

Are all the engine mounts in good condition ?

Unsure. What should I look out for? They haven't been replaced in 22 years and 90k miles.

However, on any of the engine mount problem videos I've seen the sound is very different. It is not rhythmic, and often they show the engine itself sliding etc. Mine sounds more like a cat purring.

One other (possibly related) issue is that when I stop at traffic lights etc., the RPMs still drop once to where the car almost stalls, then promptly bounce back to ~700 and stay there stably (with the 1 second periodic vibrations in the video after that).