2004 Ford Focus Rev problem

Hello,

I have a 2004 Ford Focus 1.8.

Something strange happens when I rev the engine. If the car is stationary and I rev it, the needle goes up, but once I release the accelerator pedal, the needle goes down, but it goes down below the normal idle point.

It feels like the engine is going to cut out, but it doesn't? Also when it is just ticking over, it does feel a little lumpy

I have just had a cambelt change and the mechanic said that I have a misfire. When I asked what would solve this, he said that maybe a new ignition coil and HT leads would probably sort it out?

Maybe the engine had this problem before and I just never noticed it? But now I do and I am concerned that I have a problem, or maybe something is not right with the new cambelt?

I have taken the car for a quick run, and it seems to have more get up and go now, than it did before. More responsive!

Any help would be appreciated.