An annoying problem has been plaguing the car of late; Under full throttle the car jerks and holds back before accelerating. There doesn’t seem to be much pattern to the jerking other than it tends to occur most on WOT. This got me thinking that it was either fuel or ignition related.
Since the spark plugs probably hadn’t been changed in a while, I wondered if they were worn and if the spark was either too weak or being blow out under a lot of boost pressure.
On removing the plugs, they did seem quite worn, so in went 4 fresh NGK BR8EIX plugs from Ross Sport.
I took the car out for a quick test and pleased to say no more kangarooing silliness
I was on my way to work when I heard a loud clattering and a slight loss of power. I pulled over to have a look under the bonnet, and noticed how loud the engine was when idling, it sounded like the exhaust or manifold was blowing. I could feel exhaust gas eminating from somewhere in the engine bay. It turns out one of the bolts fitted to the exhaust manifold had come undone and vacated the premises. Figuring I wouldn’t be doing too much damage, I continued to work and back home and replaced the bolt. Unfortunately the cream coloured rocker cover is now discoloured from exhaust gases, so I need to clean that up at some point.
Edit, it happened again! This time the other bolt. I got the garage to replace it and seem to have gained another 0.3bar boost. It seems exhaust gas must have been escaping slightly from the loose manifold bolts. Now the bolts are tight, it is boosting correctly and the fuelling is still fine under load. She feels verrry nippy now. Free power!