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      09-25-2020, 09:07 AM   #1
United Kingdom

Drives: 2006 M5
Join Date: Sep 2020
Location: UK, East Anglia

iTrader: (0)

Misfire - Coils & Plugs

2006 M5, around 60,000 miles. BMW extended warranty (probably not great for disposable items). Owned since around 15,000 miles/2008.
Used very little this year, recently misfired on start, but once warm, no misfire. Also showed low coolant the day after topping up.
Took to a main dealer (new area/dealer for me), who said coolant sensor fault, and that one of the spark plugs and coils needed replacement. Approved. (£150 plug/coil/labour, plus the fault finding fee of £125).
He called back to say another plug/coil showing misfire fault, and that when replaced, yet another cylinder now showed a fault. He said it might be because the fuel was low, and that when it gets low, the car starts to shut down injectors (something Iíve never experienced) and that it might be a sensor fault, so they added more petrol. No change.
He asked if he should just replace all the plugs/coils, or do it one by one.
It sounds strange that a fault would only appear on each other cylinder when fixed on a different cylinder, rather than all show up at once. There are a couple of independent BMW specialists near me in East Anglia Ė maybe itís time to leave the main dealer and try people who might be more familiar with cars of this age? Or do I just get all the coils/plugs replaced?