Strange Near Cut-Out Conundrum

[Andy JB]

My 500 has exhibited a new tickover issue when hot which isn't problematic but has potential to be....

When hot the tickover is normal then it will start dropping suddenly and either nearly cut out then recover or cut out completely but then starts fine again.

This year its had most electricals replaced as regular maintenance (coil, leads, dizzy cap rotor etc) new plugs annually and a Lambda sensor on n/s bank.

So i'm at a loss at what could be causing this & want it resolved as its due to be parked up for a few months.

Anyone experience this?

[Andy JB]

Thanks for replies & confirm suggestions as follows:-

-Engine temp sensor replaced this year so newish
-Stepper Motor done every 2k - due now but usually looks very clean at this interval - worth a try though...
-Not used in wet unless it rains while i'm out - it did this year in France religiously & ran smooth as a nut despite constant damp & standing water for 3 days!!
- Immob had new relay fitted this year & isn't original one anyway Meta 2 now fitted

Owned car for 10 years so pretty familiar with most aspects. The revs don't rise they only fall. The only other odd thing exhibited is there is a slight air type whine at tickover not noticed before but its slight & nothing jumps out with AFM or associated rubber leads leading to any air loss - its unikley to be intermittant too if it was this.

Looks like i may need an Indy to fault diagnose - but i hate to be beaten....

[Andy JB]

Yes ignition module replaced last year <5k since

Only clean stepper tip with white spirit - not sure soapy water would be a conducive approach

I'll try the stepper as an approach - never heard it close off before so i would be interested to note this

I do wonder if the lambda sensors tend to go at a similar time - i replaced offside bank ls this year so i wonder if near side bank has given up, in hindsight it does need some throttle on start up for a few moments until running smoothly which went away when lambda sensor replaced this year

[Andy JB]

Yes ignition module replaced last year <5k since

Only clean stepper tip with white spirit - not sure soapy water would be a conducive approach

I'll try the stepper as an approach - never heard it close off before so i would be interested to note this

I do wonder if the lambda sensors tend to go at a similar time - i replaced offside bank ls this year so i wonder if near side bank has given up, in hindsight it does need some throttle on start up for a few moments until running smoothly which went away when lambda sensor replaced this year