MISFIRING MYSTERY
Q I bought an MOT failure MGF VVC – fools rush in, but I used to be a mechanic before problems with mental health destroyed my confidence. The MG is a therapy project, and I have enjoyed tinkering with it, but I have a misfire that I cannot fix. One of the MOT failure problems was high idle speed and excessive HC and CO. As the exhaust had a blown gasket at the cat entry I thought it would be an easy fix.
When I took off the cat there were no innards and the silencer was split along the top. Mike Satur gave me a good second-hand silencer (thanks Mike, you are a star) and I blew my pension on a new cat.
The F was running much better but still misfiring at around 5,000rpm. I cannot give an exact figure as I was afraid of destroying my new cat. New plugs and fuel filter were fitted, as mileage is 114,000, but it’s still no better. Having bought both your books I looked at the VVC solenoids in line. I set them at 60º and tried again: brown plug to VVC housing then the blue one, but it was still no better. Next I tried a new camshaft sensor
