Hello and Merry Christmas everyone! After trawling the internet I'd like to get some further advice from you guys here before I go replacing every part in the car!
So, after having my flexi pipe changed due to it making the car sound like a proper chav car
I've had a real rough idle.... Particularly on a cold start. However, it has happened the odd time when the car is warm and stationary at the lights. I'll try my best to explain... Of a morning, when the car first starts it feels fine and the revs are where they should be. However after about 10 seconds the revs start to drop and the car rumbles and vibrates like it's getting ready to stall. It almost feels as if the cold start up cycle gets cut short? However this wouldn't explain why it would happen when warm. When I try and drive the car when it is exhibiting these symptoms it feels like it's running on 2 cylinders and when I take it out of gear and pop it into neutral it will stall. It drives absolutely fine 90% of the time although... I feel it is the idling that screws it up. A few days ago I replaced the plugs, leads, air filter and coil packs and while it seems to run better, the fundamental problem remains. There was no evidence of oil being on the old plugs so I don't think it is the inlet manifold gasket. I'm thinking to replace the IAVC valve or at least give it a clean? Maybe fuel filter? I must say... since this has started after the flexi pipe change, could it be the o2 sensor? The garage very honestly informed me my old o2 sensor was intact and it didn't require a change so they just used the old one. I went back to them explaining my symptoms but they were adamant the sensor wouldn't cause this problem but I disagree as this problem has only arisen since the change. Any thoughts guys?? Is an o2 sensor something I can change comfortable at home you reckon??
I would still suspect the exhaust sensors...I work in industrial maintenance and the two rules of thumb are, if it stops working, what was the last thing it did, points to where the fault lies, as in its waiting for something to finish before it begins the next task, or an autonomous fault, not applicable in this scenario, or whats the last thing that was tinkered with.
As the exhaust was modified and the sensors in the downpipe taken out and refitted, then this would be the first place I would look.
A possible human error, not intent, of course, but still a possibility and must be eliminated first. As in my first post, check the sensor and replace if suspect and still plug in an OBD diagnostic. It has to be done!
I replaced my downpipe 4 days ago as my car had intermittent tickover issues and would occasionally loose power. I suspect the sensors in the exhaust were reporting false data back to the brain due to the split in my flexi hose.
Good luck and hope you sort it