I got an engine management light recently and the car lacks power sometimes and feels as if the engine is holding itself back under acceleration, only when the engine is hot. It will not rev above about 3800 RPM, and seems as if it is hitting a limiter.

It is sometimes hard to start the engine aswell when it is hot. Starts fine when cold.

If I drive somewhere without stopping the engine, it runs fine, revs right up to the red line and does not lack power. But if I drive to the supermarket (for example), park up, then return while the engine is still warm, I get the lacking power problem. It seems to be going in to limp mode when the engine is started from warm.

I have had the timing chain, sprockets and tensioner changed recently, the coils have been replaced aswell, the engine wiring has been tested by an auto electrician.

I got the camshaft sensor replaced recently as that was the only error showing up. Since doing this, I am getting these error codes though (even after clearing the codes, road testing, then reading them again);

P0342, P0322, P1680, P1603, P1558, P0303

The mechanic thinks it could possibly a burned valve, as the ECU is known to throw all sorts of codes up when this happens. Is this a possibility? The engine does sound lumpy (and you can feel the car shaking too) and a bit "put put put" on tickover.

Any ideas?