Rough idle

M

memski

Guest
On the way back home from work today noticed the idle getting really low and hunting. Car runs fine when reving and boosts well as usual, but the idle is pants. I'm guessing it's the O2 sensor that needs replacing but wouldn't mind some feedback, no smoke or loss of power, checked compression a little while ago and it was the same as usual, all similar figures - will check again this weekend to be sure. Other possibilities could be a leak in one of the vaccuum/boost pipes?
 
SickBoy

SickBoy

Member
Dude im not machanical as every one knows but i had exactly the same thing turned out to be the pipe had come loose on one side of my dump valve , tightened up and all as fine again , might be worth a look

Cheers Lee
 
zia

zia

Active Member
why would it be 02 sensor? it would overfuel or lean out if it was faulty?
sound like vacuum leak.what the base idle speed when warm?you could try disconnecting o2 if the idle return to normal obviously that be suspect
idle control valve?

zia
 
M

memski

Guest
Yeah was wondering about the dumpvalve pipes, will give that a try. As soon as I dip the clutch when coming to a stop the revs drop rapidly if I coast.
 
E

Edd

Guest
hmm mine is doing the same mem, aswell as im massively down on power
 
J

j10gtr

Member
Have you got any form of checking the mixture i suspect its overfueling. You could also check for vaccuum leaks caps on throttle bodies and dump valve.


thanks
Paul
 
M

memski

Guest
Yeah, started her up this morning and sounded like she was running on 3 cylinders, black smoke puffing out the back :cry: Will have a good check tomorrow on vacuum hoses and bov.
 
M

memski

Guest
That's right :wink: and the problem is only at idle, car boosts well and power isn't down.
 
M

memski

Guest
Oh and does anyone know the part number for the O2 sensor? Not sure if it's something that Nissan will have in stock but might give it a go tomorrow...

Editted to say I've found it thanks to Fastguy on another thread :p LAMBDA SENSOR 22690-54C00 £86.00
 
J

j10gtr

Member
Overfuelling can and does cause a rough idle and a decrease in revs. Try revving the car when the symptoms show is there any black smoke coming from the exhaust ?. I reground my MAF and due to the piggybacks and the fact the car was set up without the extra ground the car overfueled and idled like a dog. I removed the ground and all went back to how it was.

Thanks
Paul
 
M

memski

Guest
Black smoke whilst idling, lots when I rev it (clears it out). Will go have a proper look in a bit.

No sensor faults according to the PFC :roll:
 
M

memski

Guest
All sorted now 8)

Went to turn the car over this morning and nothing :? Took the plugs out and they were black and stunk of fuel. Problem lied with the maf plug, took it apart and checked the connections, fired her up once plugs were cleaned up and kicked a load of crap out of the exhaust. Problem is now she idles at 1500rpm lol :roll: :cry:
 
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