Originally Posted by KC95SC400

From the repair manual, 95.

12. CHECK CYLINDER COMPRESSION PRESSURE
(a) Reconnect the negative (-) terminal cable to the battery.
(b) Insert a compression gauge into the spark plug hole.
(c) Fully open the throttle.
(d) While cranking the engine, measure the compression
pressure.
HINT: Always use a fully charged battery to obtain engine
speed of 250 rpm or more.
(e) Repeat steps (b) through (d) for each cylinder.
NOTICE: This measurement must be done in as short a
time as possible.
Compression pressure:
1,226 kPa (12.5 kgf/cm2, 178 psi) or more
Minimum pressure:
981 kPa (10.0 kgf/cm2, 142 psi)
Difference between each cylinder:
98 kPa (1.0 kgf/cm2, 14 psi) or less
(f) If the cylinder compression in one or more cylinders is low,
pour a small amount of engine oil into the cylinder through the
spark plug hole and repeat steps (b) through (d) for cylinders
with low compression.
• If adding oil helps the compression, it is likely that the
piston rings and/or cylinder bore are worn or damaged.
• If pressure stays low, a valve may be sticking or seating
is improper, or there may be leakage past the gasket.
(g) Disconnect the negative (-) terminal cable from the battery.

Notice it says 178psi or more. Doesn't say anything about a max.

If the car runs good, I wouldn't worry about it since you didn't find any indications of a problem.

BTW, fluid of any kind in the chambers could cause a high reading but you would have seen it with the scope.

KC

Originally Posted by t2d2

I'm surprised how little info there is on this topic. Per Lexus:

minimum acceptable = 142 psi, good = 178+, 240 range is great

That fits the info posted earlier by KC95SC400.