[Mgs] too rich or too lean?

[Paul Hunt]

One white plug does indicate a leak to that cylinder somehow, although as 
cylinders are paired that's not strictly logical, unless it is on the No.1 
side of the gasket which would affect No.1 more.  However vacuum leaks 
usually tend to be 'stable', not come and go like electrical problems.  The 
HT tests are really only valid if you can reproduce the problem with a 
timing light connected.  You say it only happens at speeds over 45, but 
engines are usually rev affected not speed affected.  If it happens at 45 in 
top, how about the same revs in 3rd?  And 45 in 3rd as opposed to 4th?

PaulH.

----- Original Message ----- 

> I'll try to incorporate other suggestions in to this reply too.  I  found 
> myself to be shockingly tired all day yesterday, so I didn't get  out to 
> do a whole lot of troubleshooting.