Hi all wondering for anyone can help, I have a honda stream frv 2.0ltr 2002.
shes giving me an intermittent engine management light and I'm getting codes P1298, P0325 and P0420.

When starting the engine she idles around 2000 then after driving for a few minutes the revs settle down to 1000 at idle.
If I'm driving at speeds below 30mph the light stays off or goes out if already lit. When the revs get higher and I drive at a constant speed above 60mph the engine management light comes on and the car feels sluggish and like its holding back.

Ive recently had rear brake calipers changed and the knock sensor was replaced about 2 months ago but that didn't clear the P0325 fault.

Now I am wondering which part I should look at replacing or changing first. Shes and old car and I don't want to spend alot out for something else to go, but she's a lovely drive when functioning correctly id like to keep her on the road.