slight idle issue

[Rodd1s]

...or it may be a severe problem, i dont know yet.

since ive removed the engine oil breather (attached to the rocker cover) from the inlet pipe i reset the ecu so that the engine gets used to breathing in slightly colder air than before, but after doing this the engine idled perfect for the first 5 minutes, then slowly the idle became realy rough (ie: as rough as s V8 running on a single cylinder) and was slowly dying. then, just as it got to the point where the engine was gona give up it smoothed out and ran perfect again.

a few hours later the same day i started the car, idled fine and after 30 secs of driving when i came to a junction it started doing the same. at this point i noticed that the vacumm gauge was fluctuating quite rapidly between 0 and 10 in.hg. (maybe idle control valve?). i decided to try n turn round to go home to check over it, but as soon as i floored the throttle in first gear it smoothed out instantly. since then it was running fine for 4 days until today.

this morning started the car, idles fine, drove it gently as to let it warm up, but after about a minute when i cam to a standstill i started noticing the idle smoothness deteriorating. 30 seconds later it was back at the stage of idling like a V8 on one cylinder. so i kept going until i could find somewhere to pull over, at this point it was sounding like and old banged up vw beetle. followed by the check engine light. with the check engine light still on going down a hill i shifted from 3rd to 2nd bringing the rpms to approx 4000 the engine smoothed out again, put my foot to the floor and there wasnt a single problem and it idles fine. going back up the same hill where the engine smoothed out the check engine light went out by itself.

so, those are the symptoms.

it may just be that the engine needs a good service, as this is now long overdue.
thought it might be the idle control valve at first, but after today where it was running like crap for a bit even at full throttle im not too sure.

another thing... is it possible for the check engine light to turn itself off whilst the engine is still in the same run as when it came on?

next week if i get a chance i'll be giving the engine a little service to see if that helps. but other than that... any other ideas on what could cause this?

[daewoomofo]

get the car scanned. find out what caused the CEL. thats the best place to start

[Daniel]

I could be wrong but I believe that the airflow path in this breathing tube is from inlet pipe to rocker cover. If this is right removing it won't give colder air to engine.
Did you blocked some holes/tubes? This could lead to PCV malfunction and troubles you describe.

My 0.02

Daniel

[Big Jeff]

i have removed my breather pipe, and replaced it with a filter and go no porblem,

make sure you have sealed the hole up in he intake pipe

[Rodd1s]

yep, sealed the hole in the side of the intake tubing.

yesterday i changed the ignition leads and spark plugs, not too sure whether this has done the trick, but the engine seemed more stable from low temps last nite, and it was also able to idle without fault.

the old spark plugs i pulled out were completely blackened by carbon, as far as i know this tells me the engine's running rich (i'll get pictures up later).

any ideas as to why the engine could be running rich seeing as i havnt changed anything as far as fuelling goes, and the only air intake changes are the cone filter and oil breather. cleaned the throttle body a bit when i added the oil breather filter, was mostly just small deposits of oil but no solids or gunk or anything.

could it be anything to do with an overdue oil change? (eg: 18 months since last oil change - i think)

[MMamdouh]

car will run rich if:

1- injectors are leaking (start ups take a lot of time if you left the car off for some 1 to 2 hours)

2- O2 sensor is busted

recommend that you get the car scanned and see why did the CEL turn on

MMamdouh

[Rodd1s]

here's the progress for now...

i've replaced the ignition leads and sparkplugs... and there hasn't been a single sign of the idle going wayward, yet. i dont want to speak too soon, but that's what it seems like at the minute. I can also feel a HELLUVA difference in acceleration with the different sparkplugs, so maybe those NGK's had served their purpose and are just worn. the sparkplugs in at the minute are plain-jane Champion ones that were in for about 3 months before i put the NGK's in.