I wonder if anyone can help me?
Some of the reasons I know, but for the last twelve months I have had an intermitant missfire. My garage has not been able to find it, but I did find out that the garage has not been doing what it should have!
The car is a 1993 LS400, that is coming up to 270,000 mile. Since 120K, I have been using a local garage (except for the timing belt change when I go to the dealer). The car has been ultimately reliable, only letting me down when the steering pump leaked on the alternator, taking out both, also having to the power steering cooling pipe, and also one rear bearing. It is still on the original shock absorbers, and exhaust.
Some time ago I notices a slight hesitation when accelerating on part throttle, it is OK if the gearbox kicks down, sometime the hesitation is more noticable after some high speed driving, othertime its drives relitively smoothly. It does not seem to use anymore fuel (although I do not tend to use it more in sport as this reduces the missfire).
Here is the crunch, I found out that the garage has not change the spark plugs since I started taking it to them some 140K ago, this is my first job, but while I am at it, can you think of anything else I have to do to minimise the risk of this missfire continuing
Thanks in advance