i was under the bonnet the other day fixing a split tube and i noticed a little black box next to the ECU and headlights. It had a plug next to it that seemed like it should be connected so i re connected it, not thinking much of it

then yesterday i was waiting for my gf and as my engine was idling the revs went below 1000 rpm, which made the car sound like it was on the verge of stalling. before my car hane idled around 1500-1700.

ive just unplugged the box and the idle revs have returned to normal??

i cant find the box anywhere in the haynes manual and all the pictures of the bonnet do not show it there.
it has a blue wire and red wire, the blue is connected to the body of the car and the red goes under the insulation at the back of the engine bay.

any ideas to what it is. i'll try get a picture as soon as

what car.. ive no idea what that is

unless.. its not one of them crappy ebay resistor things is it

ur idling to high btw.. 900 / 1000 rpm is normal.. 1500 / 1700 is too high

thats what i was thinking, was it one when you bought the car?

when it idles around 1000 it really doesnt sound healthy, it sounds as if its struggling to keep going.

it must have been, i've never really noticed it before