Hello I wonder if I could get some help wih this. I'm not sure where to start.

The car is a 2002 Grand vitara with the Pug RHZ diesel.

A few weeks ago on a long journey with a lot motorway (100miles +) I noticed the idling speed increase as I was shifting down through the gears coming to a roundabout. After that the MIL light came on and the car seemed down on power. After a few miles I pulled in and tested it through the rev range. Rev Ok until about 3,500 rpm where it hesitated and blow out alot of white and blue smoke.

I carried on and didnt get a chance to investigate until last Thursday. I plugged a code reader in and it told me there was a throttle position sensor fault.

I cleared the code hoping that the light would come back on and give me a better indication to what conditions where bringing up the fault. ( I thik this might have been the wrong thing to do)

The code hasnt come back but the flat spot and smoke at 3,500rpm remained until yesterday when I gave it the italian tune up and hit the higher rev range a few times. Car seems to have more power now but is still idling high.

Where should I go from here?

Thanks