Polo 1.4L 2012 Model

[Rum&Maple]

Hi Folks

I had to replace the exhaust manifold on a my Polo Vivo 1.4l as it had a crack with a branch however it seems to be lacking power and does not accelerate like it did before the manifold cracked.

I have replaced the plugs, checked the coils, changed the oil and oil filter plus the fuel filter. It seems to lag at low revs and feels as if it is not getting full throttle at times. Should I clean the MAP and MAF sensors and check to see if the throttle body is clean. It was going fine before the manifold cracked so could it also be the O2 sensor as their is only sensor bolted into the branch.

I also replaced the air filter and added a bottle of injection cleaner in the fuel tank thinking it may be a blocked injector. I'm running out of ideas now so any advice would be greatly appreciated. As I'm not really mechanically minded could someone please point out to me where the MAP and MAF sensors are located thanks.