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Happens for around 20-30seconds, 15 seconds after start up when its cold. If its been driven ad its sligtly warm or still upto temp it doesnt do it.

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- does the car have a bad idle atba cold startup? And after like 10/20 min it's mich better?

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- is it worse when it's cold/damp outside?

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"Right guys, this was happening to my ST alot about a year or so ago!

to start off with, it is NOT lambda sensor related, on cold startup, the engine management system runs open loop, in a nutshell means because its cold and the cat hasn't started working yet, the ECU/PCM totally blocks off any information the lmabda sensors are trying to send it! it therefore goes into a default rich mixture mode untill the coolant temp sensor tells it "the engine is warm, start listening to what these sensors have to say"

THIS IS WHAT WORKED ON MY CAR: i am a ford tech so obviously going to fix it myself rather than paying my work to let me put the IDS computer on it.. when i started my car it would splutter and cough for about 5 seconds and then either stall or if i gave it a quick rev it picked up and was ok after that, i decided to take my spark plugs out for a look in the morning, some oily residue on them (around the electrode tip), first thought was cam cover seal leaking into plug holes, but all was bone dry, and the oil wouldnt really get past the seal and threads into the combustion chamber! so the oil was coming from inside the cylinder, but where? surely my piston rings or valve stem oil seals werent gone at 23,000mls? only other way oil is getting into the cylinder is of course the crankcase breather, so i removed the oil cooler/filterhousing and starter motor and took the breather pipe (from block to inlet manifold) off the inlet and bunged the inlet with a sillicone pipe + jubilee clip, also took the 1 from cam cover to air filter off and put a small filter on the cam cover, replaced the plugs anyway and took it a good hard blast to clear it out!

Never had a problem since!

This wont cost you anything to do other than if you need to buy a small sillicone bung and jubilee clip for the manifold (this is what supercharged owners need to do if there still running a standard inlet!

so i would wreckon this is worth a try, what i can imagine was happening was some oil vapour being present in the inlet and cylinders just before the engine is turned off at night (going to be warm and more vapour) and then whilst sitting overnight clinging to the cylinder walls and spark plug electrode! then when starting theres not a good spark in maybe 1 or 2 even 3 cylinders which causes the coughing, spluttering, stink of fuel, stalling, then when the engines been started again and given a little rev its done enought to clean the plug and then runs ok!

thats my theory anyway guys, some may argue it but it makes sense and it cured my problem

so basically vent both breathers to atmosphere and bung inlet.. replace plugs, job done!

Cheers"

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