yingus

Hi, Firstly thank you for the great forum and the the great info on here.

My Focus, a 1999 1.6 is poorly, i shall start at the beginning so here we go.

Once upon a time.... haha joking

When i bought my used focus with approx 100k miles on it from a auction it was crap and firing on 3, now and then you would feel number 4 kick in. Anyway i changed the plugs, put genuine coil pack on it and some plug leads and it ran fine for about 5 or 6 months. From then i started to get a slight missfire now and then when below 2k rpm, like taking slow corner in 2nd gear for example. As the weeks went on it got progressively worse and you could feel a slight miss now and then at higher revs now. I decided to have a look, starting by taking the plug leads off 1 at a time and revving the engine to see if the miss was still there or it was worse but it was hard to tell any difference. Anyway as soon as i had done that the engine was now only running on 3, strange i thought, maybe a lead was weak and i pulled it. I went to the local breakers and bought a coil pack off of a fiesta ( same type ) which had low mileage and looked good, i also had the leads, I put them on my car while i was still there and... It was still the same. I then lead the plug lead test again and found the suspect, It was cylinder 2 ( 2nd one from the cam belt end ). I took it out and put another one in ( checking the gap first ) and it made no difference & the old plug was not fouled much apart from a bit of build up. I put a plug on the lead to check if there was a spark and yes, a good bright spark. I then thought to myself it has to be fuel, I had a couple of spare injectors at home so got one, gave it a good soak in carb cleaner before installing it and still no difference. I have pulled the MAF sensor off the airbox and it runs worse so i guess that is ok, i have not checked the throttle idle control yet and i have not tried a compression test either as i don't have the tester. If anyone has any ideas at all then please let me know as it's starting to send me nuts!! I have tried most things people mention apart from the 2 i stated but surely they would not stop it firing on 1 cylinder but i could be wrong. Oh, I also took the battery off overnight to see if it would reset the ecu, also did the dash test thing and no errors on there.
Thank you for any feedback it is very much appreciated.
( Sorry for the long story )

escortmk3rwd

coil pack cps a lead or dicky plug also if engine had jet wash check down holes were plugs go any water down there causes misses get pair grips leave ticking over pull each lead off 1 by 1 find out or belts jump the list goes on

yingus

Yeah i know which plug it's not firing on, i did that check, like i said it was missing now and then and slowly got worse untill only firing on 3 constantly. Anyway today i put on a used throttle sensor and no difference, i checked the plug lead of the suspect cylinder and the spark is not constant, it will give a little spark once every 5 seconds or so but if you hold the plug very close to the rocker cover it will constantly give a small spark. I don't think it is the plug as it's a new one i tested it with so maybe a weak output from the coil pack not giving it enough juice to jump the plug gap. The coil pack i have just changed as my old one was the same but it is not a new one. I know it could be possible the used one i just bought is also faulty but i find that hard to believe as it's the same cylinder as before so surely it's some where before the coil pack, Maybe a faulty ECU or something ??? It's doing my head in now haha...

escortmk3rwd

swap plug and lead timing mightve jumped or could even have a stick valve

yingus

swapped plug and lead, i doubt it's the timing slipped as it was missing then ok and got worse and then was only firing on 3 so can't see it being the timing, all other plugs firing fine, it's only 1 that has weak or hardly any spark now. I think i am going to take the ecu out and have a look at it, i like to tinker so worth a look to see if there is something wrong with that.