Fuel Injector Cleaner update - Dan J
For anyone with a petrol car that is a few years old the following might be of interest:

1.8i Cavalier 1993 MY [with catalyser]

Week ending 04/11 = 35.8 mpg over 411 miles
Week ending 11/11 = 36.1 mpg over 386 miles
[Average = 35.95 mpg]

After using STP Fuel Injector cleaner in two-thirds of a tank of petrol

Week ending 25/11 = 38.1 mpg over 427 miles
Week ending 02/12 = 37.7 mpg over 372 miles
[Avergae = 37.9 mpg]

All 4 weeks very similar driving speed/traffic-jamwise over the same routes.

As I drive approx 400 miles per week this represents a difference in just under 3 litres of fuel per week which equates to a saving (at 72.9p/litre) of about 100 quid a year.

Not bad for something which cost a fiver though it does specify usage every 3000 miles. Just as simple is buying a gallon of paraffin and using (I think David W's) suggestion of 1ml to 1l every month or so. The car also runs much more smoothly at constant revs and there has been a slight but noticeable improvement in idle stability.

Dan J
Re: Fuel Injector Cleaner update - El Dingo (Martin)
Does HJ recommend this? It certainly seems worthwhile...

Value my car