Power loss after cambelt change

[bigcatface]

Recently I changed the cam belt on my 1.4 mk5 polo (engine CGGB) and the car is now down on power. Symptoms are pointing towards retarded timing (I had used a cam lock however I may have knocked the crank pulley?) but there is no engine warning light. Is there a funny grey zone where there could be an issue but the engine hasn't quite figured that out?

I do remember specifically there was a slight amount of play in the gear on the crank so I may have lined the belt on the wrong tooth. This may be enough to knock off timing.

Outside of this I can only think that something is too tight and is robbing power?

Any ideas would be appreciated!

[iichel]

verify timing is correct is step 1!

[bigcatface]

From reading around I do suspect that I could be 1 tooth out on the crank gear. Will report back when I get a chance to look