Help needed please?

[B41LEY 0]

Car has been loosing power at about 2500-3000 revs when the engine is warm, sometimes you can drive the car fine all day and other times its every couple of miles. I assumed there was a problem with the petrol as it feels like the enging is coughing and starving of fuel. I've ran some red-x through it and changed the fuel filter but the problem just keeps happening.

 

On driving home this evening it lost power when coasting up to a junction, i floored the accelerator and it wouldn't rev past 1000! The exhaust was popping and banging a lot and the car sounded dreadfull! I opened the bonnet and heard the k+n airfilter sucking really loudly! I gave it a wobble and all went back to normal!

 

Obviously too much air is getting into the mixture and causing the rough running, i've checked all the air intake system and everything seems tight and fixed in place as it should be. The only thing that seems a bit odd is the small black box in the photo below is making a lot of noise, i can't feel any draft coming from it so i assume its sucking? If someone could please tell me what this part is and what it does? Sorry for the long explanation, thanks in advance IanSDC10541.JPG[/attachment:2s9m9pnh]

[CazzaVR 0]

That's the ISV damper pot. Basically it's there to quieten things down a bit and is full of sponge. Take it off and give it a close inspection- these have been known to split and explode from time to time! Makesure the sponge is still inside. If not, check the hoses and make sure it's not been sucked into one of them. This could cause the probs you describe, or an air leak.

 

You can actually delete the damper pot completely with no ill effects. Just buy some decent hose of the same bore and instead of it routing from the ISV-damper-engine, route it straight from the ISV-engine. In fact, if you twist the ISV round a little, you maybe able to use one of the damper hoses. Undo the leads and take the black plastic engine cover off- makes access much easier ;)