Sounds like it could be the Lamda/O2 sensor. With it being a UK '99 I'm sure it doesn't have the coil packs the same as the older imports, it has a single coil with HT leads down to the plugs as far as I know. The standard oxygen sensor is only a narrowband one and trys to keep the mixture close to stoich, but it waves back and forth as it goes over the middle voltage (0.5v I think). Can't remember which way it goes but as it gets one side of the voltage the ECU leans the mixture till it passes over the 0.5v then it makes it richer till it passes it the other way. When it starts to fail it sends wrong signals to ECU and may cause it to hunt excessivly. Also as far as I know the standard sensor is only used at low rev/load situations and when you put your foot down it goes open loop and runs purely off the maps so should run fine in those conditions. I'd unplug the O2 sensor and see if it cures the problem. It will bring on the CE light though when disconnected. Someone with more knowledge may come and confirm this or put me right, but thats where I'd start. Lamda sensors last about 60k.

 

so it could be, icv,o2,plugs,leads,coilpack? this is getting a bit mad,at the moment im convinced its the icv,02 or plugs. maybe someone will make some sense of this.like i said im hopefully going to eliminate the icv soon.

 

right i have eliminated icv,it is not the icv,so its now looking like lambda sensor or coolant temp sensor,or possibly plugs but doubt it,which is more likely with the symptoms i have?

 

It's dash side under the inlet manifold as in the picture i posted above and you do know that the coolant sensor is approx £30 so will not break the bank.

But yes its advisable to try the mates ICV first as it's free, just ensure you mark where his ICV located on his as you don't want to be playing around with 2 bad idle motors.

 

marking the valve is not an issue,already tried my mates one and my car still did it,r u 100% sure its on the dash side cause i had a quick look and it looks like its fitted to the crossover pipe on the headlights side.by the way the icv i tried was in perfect working order and has never had an idle problem,thats how i know that mine is fine.

 

Mate the picture i posted clearly shows it on the water crossover pipe....and its driver side of the crossover pipe.

as shown in the pic>>>



At the bottom of this picture is where the gearbox mates to engine and the person who took the picture was standing next to the front wing drivers side.

 

Everyone seems to think it is 90% the same problem they've had before, only there are about 6 suggestions on the table.

The best thing you can do if you can't afford anyone to look at it is to by a £13 pound cable off ebay connect it to your obd/select monitor port, and using rom raider you can view/log all of your sensor outputs.

They are really good for all sorts of testing, including MAF voltages etc.

What it can't tell you is if the coils etc have gone, but once you verify that all the engine sensors are working only the coils, leads and injectors are left.

If the car is misfiring due to coils/leads then the oxygen sensor reading will go high and you'll be able to see this.

I have my cable perminantly fitted and routed through to the passenger footwell so I just plug the usb into a laptop to diagnose or log.


PS You might need to borrow a laptop if you don't have one...

PPS A faulty crank sensor *may* cause this problem, I know its possible on other cars, not sure of scoobs.

 

thanks to everyone on here,been a real good help,car is fixed today it was the spark plugs,cant believe it,ive even gave her a clean to celibrate!

 

Bugger! Was hoping you was going to say something else had resolved it - cos Ive already done that Glad to hear youve sorted the problem though matey Am going to try the temp sensor next

 

yeah sorry bout that mate! car drives,performs and idles perfectly now. u will get there in the end!

 

what plugs did u have fitted? and what did u replace with

 

i had ngk6's and i replaced them with denso iridium ik22 gapped to 0.7

 

to see if the idle is better

 

My car is finally sorted also Turned out that the Blitz dump valve that has been on the car since I bought it was playing up. I was in API having a gearbox, clutch and flywheel fitted when Nathan in the workshop suggested that might be that - he then tested it - found that it was at fault and put a new one on finally sorted!!!

So a big thanks to David for his technical advice and fitting me in at such short notice, a big thanks to Nathan for sorting out the dump valve (cos its been bugging me for ages) and also the technican who fitted the box etc (sorry but I didnt catch your name!!). I would definately recommend API

 

That was Kev, he drives a Skyline, but aside from that, he's quite a nice bloke

Thanks for your custom Mark. Glad to know we got it right for you.

David

 

Looked like quite a nice Skyline though, noticed it in the car park and thought it must be one of yours Speak to you again
Cheers
Jenks

 

Big-up to the David for exclusively being a dyed-in-the-wool Scoobster!

 

Hey Guyz, now ive got the same problem. Ive had new plugs put in and a maf. but it still idles up and down and its lost power too. minez a v4 type r. any1 plz help...