2000 Z71, ERRATIC MISFIRE, NO LIGHTS, NO CODES, VERY LITTLE POWER, ENGINE SHAKES LIKE CRAZY, GUESS ITS BECAUSE OF MISFIRE, NEW PLUGS, NEW WIRES, NOT A PLUGGED CAT, ANY IDEAS?

erratic compression indicates a cam lobe problem or cam follower problem
with that many miles on it , the cam shaft will have wear on it but the rest of the motor will have considerable wear including possible ring problems on the numbered pistons
If the body is rust free consider a new -out of the box engine as a cheap plug to stop the repair waste of money

The flashing light is indicating a misfire which is what you are describing. When is the last time you had a tune up? Most likely just replacing the spark plugs/wires will fix it.

if the mass air flow sensor is dirty or bad it can result in a backfire and run rough. A high level of impurities in the fuel can clog the fuel filter and prevent it from propelling the appropriate amount of fuel to the engine. its very hard to tell, there are many causes. from timing to engine tuneup plugs etc. to vacuum leaks in exhaust close to engine. hope this helps you! if you did install new plugs it may be the wires or a bad coil.

Do you have a service light on or check engine.If the car shakes when it is not moving it is not the brakes.I would guess an engine misfire or poor engine preformance if it does it while idling.An 11 year old Volvo is probaly ready for some new plug wires and spark plugs if it has not already been done.Good Luck!

If the shaking is caused by the engine missing (a misfire on 1 or more cylinders), then
check your (a) spark plug wires - pull each and check for continuity/faults/burn marks/etc., (b) spark plugs - pull each & check for fouling/faulty/etc.
Another good check for spark plug wires is to park in a dark area at night (open garage with the
lights out works), run the engine and observe the engine operate in the dark - little lights caused by
faint arcing means that the wires are leaking electricity to the engine block, instead of delivering it
to the spark plugs, like they should.
Your particular car has a Distributorless Ignition System (DIS), consisting of an ICM (Ignition Control
Module) connected to an individual coil pack for each pair of cylinders. You'll need a
HEI (High Energy Ignition) ignition system tester (about $30-$45 any auto parts store) to test
these coil packs, which I have found quite easy to replace (usually a couple of 10mm cap screws).
Since the car shakes only when accelerating or going uphill, I tend not to think that suspension
components of the car are at fault.

check to see if your firing order is correct

i think he is wrong ....check plugs wires and for vacuum leaks common for intake gaskets i have changed 3 this year and all had cyl misfire related codes

P0304 Cylinder 4 Misfire Detected P0354 Ignition Coil 4 Control Circuit P0204 Injector 4 Control Circuit You need to check injetror wires an coil wires .If good, The new coil my not be good.The Injector my be bad. If good it the ECM Check all fuses.

we have the same problem down to the lights and everything
Did you ever figure out what it was?

try by replacing plug wires and spark plugs, also add some fuel injector cleaner to fuel tank, i will recomend techron brand or si1 from red line but you can use almost any one