Misfires on low rpm during acceleration and unstable idle

[Kieran.200]

Hi all
I have a mark 3 clio rs 200. And it misfires on low rpm between 1k-2.5k in n acceleration. It all started when water leaked through the washer jet down into the spark plug well above cylinder 4. All 4 spark plugs and coils were replaced. Problem still persists so far it’s had new injectors, throttle body cleaned, engine adaptives reset via clip, compression test which was ok, electrode gaps on spark plugs checked, map sensor o ring has been replaced and has the aftermarket bracket on top, new fuel, upstream and downstream 02 sensors are all giving correct voltages as well and there is no fault codes. It also only starts to miss on acceleration once it’s warmed up Anyone had this issue before?
Many thanks

 

[superfly]

Hi , I had a simular issue with mine, also caused by water from the windscreen washer leaking through the bonnet holes and also the washer jet hose split.
I messed around for ages, replacing the knock sensor and trying to find the problem by replacing each coil in turn with a new one I'd purchased. Eventually I singled out one coil and replaced it and although the problem was greatly improved It still had a slight missfire which got worse over time. In the end I bought a complete set of new coils and the car runs sweetly again.

I'm not sure how usefull this is as i assume you replaced your coils with new ones but the origins of the issue seem identical. I lso had no fault code or dashboard lights.