Have you got a timing light? If not, first set the engine to TDC. The notch on the inner side of the camshaft sprocket should be level with the top of the cam cover, and if you look through the hole in the gearbox bellhousing (plugged with a green plastic plug) you should be able to see the TDC mark on the flywheel - either a "0" or a little square block. If you can't see it, then turn the engine over again so the cambelt sprocket mark lines up with the valve cover, and you should be able to see the TDC mark on the flywheel. Now take off the distributor cap. The rotor arm should be pointing at a faint notch on the lip/edge of the distibutor body, right where the cap would normally be sitting. If it isn't pointing there then loosen the clamping bolt at the base of the distributor (where it goes into the engine) and turn the distributor body itself until the rotor arm lines up with the mark. Put on the distributor cap and the timing should be fairly close. To set it totally accurately you'll need a timing light, or take it to a garage and have them set the timing - it'll only cost a few quid.
I would say that getting your timing checked is gonna be pretty high up on your list, for the cost of it ( a tenner at most ) you can rule that out. Depending on how retarded or advanced your ignition is will have very different effects on your engine, I had a 200sx turbo, that was overly retarded, and would get to 5000revs and not go any further. I havn't read your other post, so just tell me, does the problem seem better or wose.. or the same when the engine is cold.. I only ask, as the car advances the ignition timing when cold... Andi
Emma, all the other replies are pointing the finger in this direction. If the timing adjustment sorts it great, if not then as above there are other things to suggest. Without seeing the car everyone is just giving a good educated opinion.
