Strange problem has developed in the Zed
 

So driving down the motorway this evening and the car developed a strange problem where it wouldn't pick up speed over 100 KM/H on the straight and level stretch of the road then once a down hill section came up she sped up to 120 KM/H and then up hill, down hill and on the level she stuck at 120ish not a bother. I am thinking either TPS or Camshaft position sensor. Any ideas?

Hi buddy I had this problem with the silly plastic inlet manifold as you prob no you have 2 vis moter 1 is for low speed rpm and other is for higher speed rpm. I found when my vis moter was on its way out I had trouble geting the desired speed then it would just be fine I would prob suggest over next week keep eye on car if the problem persists then I would suggest asking one nice people on this form if they got vis testers or a indicator kit

It's not a v6

Ah well I'll have to rethink that,sorry didn't realise

Sorry should have mentioned it's a K-4

Any slack in the throttle cable? Is the throttle fully open when the accelerator is pressed to the floor?

Throttle cable is tight so I would assume the throttle is opening fully when the pedal is down to the floor and there is no play in the accelerator pedal either

Isn't it a 1.6?

What were the engine speeds?

it's a 1.4. The engine speeds were around 4K @ 75 MPH