The car is a 1993 Rover 420 GSi Turbo (petrol)
I'm trying to solve a problem of random jerkiness under hard acceleration. The jerkiness happens when the engine is warmed up/hot, and gets progressively worse.
I've checked the spark plugs, they had a black sooty ring around the base of the thread, a dead white insulator nose, and the cathode? (the bit that you gap) is vey clean. Is this due to overheating?
If the engine is overheating, what should I check? All the temp guages seem to be working OK, but it's funny that no matter how hard I drive it the dash temp guage never gets above half-way.
Thanks, Steve :)