Have you checked the fuses, they get dirty. Other causes could be engine temp sensor MAF sensor or now my favourite...the fuel pressure regulator. On my car it seems the regulator wasn't dropping pressure at idle and so pumping gallons of the stuff through making it go lumpy and rev up and down etc.
It'll be near the fuel rail connected to one end probably via a short piece of fuel hose and have a small vacuum pipe going to the intake manifold or air plenum. It'll also have a fuel return pipe at the bottom of it.
took the red 155 for an MOT and it failed on Hydro carbons.
.Car hunts on tick over
.Seems to be holding back then clears giving the brown stuff in my body a way out.
.Injector light comes on.
Any ideas please
I had this one on my car, turned out to be a leak in one of the four rubber pipes that join the inlet plenum to the manifold. One had been tucked inside itself along the underneath causing the leak. Resulted in the holding back when pushing the engine hardest, when accellerating from low revs in a higher gear (3rd to 5th). Luckily they are less than a tenner each and not too hard to fit, though the whole lot has to come apart.
id almost bet my dinner that you have an air leak....inlet rubbers or inlet gasket....spray WD40 all around it with it running if the revs change youve found the leak.....an air leak will instantly give high HC and also hunting.