low idle/engine shake

[lealan38]

Hya i recently had a fair bit of work done on my car at a BMW specialist who said the engine is ok and then soon after it developed an idling issue where the idle has dropped to around 600 from 900 and i can't work out why. The engine now shakes quite a bit at idle but otherwise runs ok. The garage said to check for air leaks, so i did and can't find any. So far i have, cleaned out the ICV, done the spark plugs and gapped them to spec, checked the air filter,checked mounts, tried to remove the 02 sensor which will not budge, oil change, oil filter gasket changed, and a bit of air intake tinkering. Thats it and no change. Is there a way to alter the idle manually like a screw or.....? Any answers appreciated. Lee

[ron]

Hiya not sure if this will help, you did comment on a post i put on about fuel consumption, although my car runs really well it did have a bit of a hiccup when idling the revs would suddenly drop from 600 rpm to below 500 rpm and almost stall , it only seemed to do this when hot, i tried lots of thing as you have done inc a new coil pack's all to no avail. so then i looked at the MAF (mass air flow, thingy ) this on my car is between the air filter box and where it goes into the inlet, I just undone the pipe clips and took the whole thing out and gently sprayed it with electrical contact cleaner a few times ( THIS PART IS VERY DELICATE SO BE CAREFUL) refitted the maf and first day made a bit better, but since then the more a use the car it seems to have cured that problem. hope this is of some use to fixing your problem

[lealan38]

Thanks. Will try this hopefully tommorrow.

[lealan38]

Just took out the MAFS and cleaned it ,put it back but still no improvement. Ah well.

[lealan38]

Latest is, i have put brand new performance spark plugs in and purchased a fuel filter and coil plus leads. Fingers crossed but have a feeling that possibly because of previously adding oil leak fix treatment and redex also its messed something up? Maybe the O2 sensors dirty as the exhaust sounds a bit clogged? More dosh....lol

[lealan38]

Changed coil and leads, and fuel filter and still no improvement. Am going to purchase an aftermarket intake and change the lambda sensor.......soon. lol

[ron]

I guess if nothing shows up if you get a diagnosis test, you can really only try one thing at a time to eliminate the problem, i would ask your local mot station to see how your cars emissions are, this may determine if you need to change your Lambada sensor as i believe they are not exactly cheap to buy. Not sure about your car but mine has 4 two before the cat and two further down the exhaust, but its the one/s that are before the cat that would cause running problems and high emissions , so ive been told by others anyway. Good luck anyway hope you find the problem soon without to much expense

[ron]

Just a thought, when you changed your plugs did you notice any difference in colour of the electrode on any of them? were they all about the right colour? if 1 or more looked different I would give your engine a compression test yourself, make sure they are all within a few PSI of each other.Low compression on one cylinder will deffo make idle very shaky but may not be that noticeable when running!!!!

[lealan38]

I didn't notice anything abnormal about the old plugs . They were all the same, no oil,soot or red etc. OK will try a compression test. Cheers Ron.

[lealan38]

Things got worse a few days ago. I emptied the coolant to replace before it gets cold here in Uk and bled the air etc. Thought was ok but now am getting overheating and the hot airs not working inside? Wish i'd have left alone! I tried to bleed out any airlocks but just a load of steam n some water spluttering out. Any ideas? HELP! Would it be the thermostat or matrix???