Does your car’s motor get regularly serviced? Before attempting to play about with electronics/sensors, I’d want to be sure that the air filter, oil filter (and oil), fuel filter and spark plugs are all in good condition.
A tick-over around 650rpm sounds about right for me Provided that the tick-over is smooth and steady, you might be looking at a clutch and/or throttle-pedal problem if your car now habitually stalls when pulling away. If the tick-over is uneven, cleaning the throttle-valve is suggested online, but that’s not something to consider doing if there’s a simpler cause (eg. dirty spark plugs).
When you say your car “...has cut out twice at the lights”, does that mean the motor was idling ‘normally’ at around 650rpm with the car static and then just stopped, or that it stopped when you attempted to pull away?
(I notice from your earlier forum postings that you have owned your i20 for at least 5 years, so it might be worth knowing the vehicle’s current mileage.)
The car's getting serviced soon so will replace all the filters inc cabin. Can look at the throttle while under the hood.
A new set of spark plugs were fitted a few months back when it wouldn't start after standing for a few days. I put the new plugs in yet still didn't start. Plugged in the code reader and although no faults, I did an erase and the engine then spluttered into life.
Have changed the oil and all filters today along with fitting a new cam sensor. Idle is now and about 200rpm higher than normal when cold but the engine still cuts on when warmed up. With a bit of throttle, the engine seems to run fine.
Will look at the throttle valve tomorrow.
Should a stretched timing chain be the culprit, can it be changed with the engine in situ on a 2009 G4FA?
Got the car driven to a local garage and his computer reported crank position error.
Drove home (1.2 mile) but just as I was getting on the driveway, it started to rattle like **** then wouldn't start any more but would crank. I've taken the rocker cover off and the chain is still on the sprockets. With the o/s wheel up, in 1st gear and plugs out, the engine seems to be locking unless I rotate it backwards a bit first but backwards, the chain jumps on the rear sprocket.
I suppose there will be valve damage now so its a head job too as well as timing chain. Being a 2009, may decide to scrap the car.