When the metro is idling it is ticking over fine, then all of a sudden the revs drop to near 0 and then instantly pop back up to normal. Like the car is having a little cough.
Here is a video:


It has done this as long as Ive had it but its been pretty rare maybe once or twice a day, but today its been doing it everytime Im stood still sometimes straight after each other.

Any ideas?

Im thinking its sensor issue, as if the revs really dropped to near 0 it would most probably stall or at least the oil light would flicker.

Cheers

Loose wire?

a real good service. ht/spark plugs could be breaking down.

i serviced it on saturday, brand new filters, oil, plugs. Its probably been worse since.

Didnt change the leads though.

Quite a few things, might be a carb issue or an electronics glitch. Sounds like it could be a fuel supply issue but that would repeat.

My Mazda used to have that same hiccup, I never did suss out what it was.

could be a million and one things.... whats odd is that its so smooth/steady between the glitches

i wouldnt expect it to be the HT leads... youd really expect it to be a constant problem if it was...

Id check the vacuum hose going from the air intake manifold to the carb... check it for leaks/holes/kinks etc..

is it very regular ?  does it just happen randomly, or does it keep happening after roughly the same amount of time each time ?  say every 7sec ish ?

Its an injected k-series, no?

I cant hear if its dying or not, but its too precise to be an IACV or vac issue I think

Could be ignition, could be a lot of things!

Do you have a fault code reader

yeah its MPI VVC.

The engine note changes when it happens and the car vibrates, if you turn the vid up you should be able to hear it.

ive got obd reader and software, not sure if the metro has a plug tho, ill check tomorrow.

It happens completly randomly from what I can tell but today alot more frequently than ever.

I had a similar problem but this was on the golf it ended up being a VDO Sensor.

Again it started off happening now and then, then all of a sudden it was all of the time. May be worth stripping out all the sensors and cleaning them to ensure everything is good

Oh has it started giving you any deadspots under heavy acceleration?