Coolant Leakage Solved- BUT . . .

[Kerry Griffith]

I believe I reported that the second new coolant reservoir cap solved 
the first leak. When we last left our hero, the second lead appeared to 
be from the radiator or hose. According to my mechanic, the reservoir 
tank had a leak that sprayed coolant onto the radiator area. New tank 
resulted in no more coolant leaks.
BUT . . .
Still no explanation for the following: After the car idled in 101F 
with A/C on for 10 minutes, it ran very poorly- the instant the turbo 
began to  make boost it would hesitate briefly until there was no 
positive manifold pressure, then run normally until the next 
application of anything but the most delicate throttle. After 10-15 
nervous minutes on the highway at warmer than usual but not overheated 
temps (no extreme gauge readings nor warning lights) the coolant and 
oil temps dropped a bit and the car ran fine for the remaining 20 
minutes home. After letting it cool for several hours it ran fine.
My mechanic has no clue- says he's never encountered this before. This 
happened when my coolant leak was operational, but since the car cooled 
sufficiently so as to be within normal temps after 10-15 minutes on the 
highway, I assume it is a different and as yet undiagnosed problem.
Since my mechanic is as clueless as I on this one, I once again seek 
group wisdom.

BTW, I've driven the car about 100 miles in 80-90F and behavior is 
normal but for the need to apply throttle at start up (20% of the time 
only) and never more than 1.6-1.7 bar indicated for the last 6-12 
months instead of the 1.8 we enjoyed for years.

Another (yet another!?) tiny vacuum leak?
Help! I don't want to be Turning Japanese!

Kerry