engine itermitant heavy missfire

[jamo]

hi i was wondering if any one has any idears on an intermitant heavy missfire i have on my 93 wrx?it appears to be flooding when cold which is causing the plugs to fowl/missfire,this problem goes when engine is hot and dosent happen every time!i have renewed the coil packs and the plugs.if i change the plugs the problem goes for a few weeks and then returns until the missfire gets so bad that the car is nearly undriveable when cold i remove and clean the plugs and clean them and its ok again for a couple of weeks there is also a very strong smell of fuel.i have also change the air flow meter and now am considering the problem may be the coolent sensor? but this is a guess also there are know flash codes in memory! any help with this would be greatly appreciated

[matt]

could poss be your lambda sensor in the exhaust headers, if it is faulty then your car could be running very rich when cold, hence the over fueling and and the smell of fuel, hope this helps ?

[Broxi]

i had the same, it was one of my plugs.

[bob]

If you have cel flashing now and then try recalling them by connecting the 2 wires under the dash. I don't have the link with me at present but i'm sure some helpful person will post it. Lambda does sound a likely cause.

This one...http://www.saxonfields.freeserve.co.uk/Scooby%20Page/ECU%20Diag%20Page.htm

[Mr H]

could be cold start/idle valve sticking

[jamo]

have checked flash codes none in memory,already tried new plugs and coils.have fitted new engine temp sensor as it was cheaper than oxygen sensor,all behaving at the moment but fault may return in a few weeks in which case i will try a oxygen sensor thanks for everyones help!!!

[Mr H]

if problem comes back try ngk bpfr7b plugs just a bit hotter cured the same problem on mine but at the same time i cleaned lamba sensor and the terminal block for it wich is just under the header tank the red wire terminal was corroded up cleaned it put it all back together and it has been fine eversince hope this helps