Polo Typ9N3 ECU Error Codes

[DJPT-UK]

2005 Polo 1.2 E (55PS)

I got an engine management light recently and the car seems to be lacking power sometimes and mis-fires under acceleration, usually when the engine is hot. It is sometimes hard to start the engine aswell when it is hot. Starts fine when cold.

These are the error codes I am getting (I cleared them, ran the car for a few days, and the exact codes came back two days later);

P0342
P0322
P1388
P0303.

Compression test done aswell;

Cylinder 1 - 10.5 bar
Cylinder 2 - 7.5 bar
Cylinder 3 - 7.5 bar.

Coils and spark plugs have been replaced recently, and swapped around to see if mis-fire moved and it didn't. Engine wiring has been tested too by an auto electrician. Thottle body removed and cleaned, hoses and vacuum pipes checked aswell for leaks.

Any ideas what the fault could be?

[vc-10]

Well, shouldn't the 3 cylinders have the same compression pressure? The exhaust valves are known to die on these engines, but I'm not sure if a 2005 car would have any issues with that.

[itavaltalainen]

Would suspect crank- or cam-position sensor, could well explain ignition timing issues leading to knocking and misfires. Would check timing, you'd see the same thing if chain has jumped!
Low and uneven compression, not too good...