you havent checked your airbox cold air pipes. Imagine trying to breath with big Tyrone with his hands around your neck - id have thought it to be pretty darn difficult. Well, thats what your cars doing if you left it up to someone else other than yourself to put the airbox back together!
I drove away from my house today thinking: "this car feels very strange and not a smooth power delivery". Its done this before and id forgotten exactly why. I popped the hood further down the road and had a gander at the airbox, only to find that the cold air feed pipes were connect to the airbox in the wrong order! This caused one of them to be completely crimped shut forbiding any decent air flow! The other pipes was also curver awkwardly. I swapped them over to their correct places (not even connected properly-very loose!) and i had to squeeze the pipes to their correct shape. This has happened twice after ive had it in the garage.....
Make sure you check yours because it makes a HUGE difference. The biggest difference was the speed in which the car decelerates on the motorway. With the crimped-pipe conversion, it decelerates really badly when off the gas. But with the pipes in their correct locations it is much more smooth decell and it does it slower.
The correct order for pipe connection (Mk.1 anyway) is: front grill to top of airbox and wheel arch feed to lower airbox. They fit into their slots so much easier and the pipes are their correct (non crimped) shape.
Hope this helps
Could be why loadsa 172s are slow ones?
