The air filter housing supplied with the 194bhp (ES9J4) engine is known to have a serious design flaw which has severe safety implications.
Inside the lip onto which the air hose to the throttle body fits, is a steel band. It has been reported by several owners including myself that this band can come free during driving and be sucked towards the throttle body where it will result in the throttle being forced wide open and the car accelerating uncontrollably. Below is a guide to removing the band before it causes trouble. It should only take a few minutes to complete.
If your throttle does become stuck open:
- DO NOT panic.
DO NOT try to overpower the engine with the brakes (even on a coupé with Brembos) as you will melt your brake pads
DO NOT turn the engine off while on the move, as you risk engaging the steering lock. You will also lose steering and braking assistance.
DO NOT let the engine bounce off the rev limiter with your foot on the clutch - you will burn out the release bearing and have a very expensive and/or long job ahead of you.
DO put the car into neutral and come off the clutch
DO let the engine bounce off the rev limiter
DO gather your senses
DO pull over where safe, and then stop the engine
DO evacuate the car of all passengers if it happens on a motorway or fast road - get everybody behind a barrier before contemplating repair or recovery
How To Fix:
This is the 194bhp ES9J4 engine shown in a D8 coupé. The 211bhp ES9J4S looks very different.
Undo the jubilee clip holding the air hose onto the rear of the air filter box, and pull the hose off.
You should be able to see the steel band now, although it may be tucked further into the air filter box than is shown. Remove it.
Many thanks to "Mr Bob" on the coupé club for permission to use the pictures