Nearly stalls when pulling up at the lights

[justice4all3000]

Had this problem for over a year now, I heard that it can be caused by the iac valve not moving quick enough I have tried two second hand iac valves from the wreckers with no luck is this a common problem? would it be worth paying for a brand new iac control valve?

[chrisdoesitbetter]

if its only happening at the lights, i dont know. try checking your brake booster and vac lines if you havnt already...

[justice4all3000]

I had the brake booster replaced with a brand new one 3 years ago

[HoldrodeoLT]

Is it surging?

[neet_wagon]

I assume it gets serviced? One of the following could be an issue:

- Clean throttle butterfly, it may be sticking closed at off-throttle idle
- Fuel pump, though a year seems a long-arse time for a f/pump to take to die!
- And yeah, it does sound alot like a vacuum issue.

All else fails, get a new IAC valve, doesn't take alot of 'gunk' to make them play up.

Someone else may have a better idea, but without seeing/hearing it, its a bit difficult to diagnose.
Maybe ask a mechanic?

[justice4all3000]

yea I took it to a mechanic he was no help at all he just said was come back when the problem is worse!

[justice4all3000]

and yes it does surge when I pull up!

[neet_wagon]

Sounds like a tip top mechanic! It still sounds like either a fuel or vacuum issue to me.

[madsav]

sounds just like my old vp the serging and nearly stalling etc etc not sure wat it was thou just sold the car off before it got worse wat ever it was lol

[aussieghostrider]

The IAC is not alwasy the problem ..

can be -->

cheap things -->

dirty air filter ,blocked fuel filter,dirty injectors,spark plugs and leads,throttle body dirty.

expensive things -->
coil pack/dfi heats up and is causing a miss at low revs , fuelpump on its way out , fuel pressure reg stuffed, inlet manifold gasket stuffed , alternator is weak and cant power car on low revs.


try this .. change all your spark plugs and leads , buy can carbie cleaner and spray 1/4 can into throttle body and open up throttle and spray in there and look in there and you will see the IAC air inlet so spray in there as well then let sit for few minutes then get can wd40 and then spray that in there while opening and closing the throttle as this will lubricate the moving parts , change fuel filter and put bottle nulon injector cleaner and fill up with 1/2 tank of premium and go for a drive on a long road or freeway.

If you still have problem then possibly coolant temp sensor is playing up... and the oxygen sensor can also cause idle issues but usually engine light comes on and fuel consumption increase greatly.

One thing to try is when cars first started in the morning , gently touch accelerator and listen to the low revs and if you hear a miss then its definately spark plugs,leads,coilpack dfi as this is what happened to me trying to sort out the miss even when engine was cold it had the miss and coil pack died year later so replaced with new vp one.

I have spent thousands on my vn only because it's 1 owner and got less than 220,000 it. replaced 90% everything ... only things original are the engine,transmission,diff and the computer.

[HoldrodeoLT]

Can be a combination of things.. ive have similar problems.. once i started surging and i stalled all together doing 80 km/h sailing an almost 2 ton ute with no power steering is fun.

Fuel pump,EGR valve, Computer issue, IAC valve clogged, fuel pressure regulator, o2 sensors, dirty MAF sensor...

Have fun soughting this one out.. i almost pulled my hair out figuring this out on my ute..
Untill 1 day i read some where that crap acceleration down low (which i had badly)
is the cause of a dirty IAC valve.. sure enough the TB and the IAC valve where so carbined up im suprised anything got through.

I cleaned it up and sure enough its been a tottaly diffrent car... happy hunting

[justice4all3000]

I might add that the problem only happens when the engine is hot and I have cleaned the hell out of the throttle body lol

[aussieghostrider]

ok if its only doing it when hot then ... spark plugs , spark plug leads , coolant temp sensor to ecu , oxygen sensor , dirty air filter , fuel pressure regulator stuffed or damaged hose, Crank angle sensor on its way out , or more expensive the coil pack/dfi ...

you replaced IAC with a 2nd hand one that was clean and adjusted properly ?

do this ... take off positive battery lead for 5 mins then put back on and then start engine let idle for bit then rev car half throttle for 10 seconds to reset the IAC and the computer .. then go for a drive and see if it gets any better.

But it sounds like the coilpack/dfi is heating up and struggling to give a strong spark to the plugs so it's missing and wanting to nearly stall at lights but when accelerating is getting enough spark.

the alternator and coil pack/dfi can cause problems you have ...

I think you have to do an error code check ... or take it to someone ...

One thing I must mention is that my tensioner pulley arm spring is on its way out so when engine warms up the spring gets warm and I get a rattle noise and low funny idle when stopped at traffic lights so it might be that as well.

let us know how you go ..

[justice4all3000]

I gunna go with the coolant temp sensor! I have a feeling it might be it because the thermo fan never kicks in however it works fine when I turn the air con on,
hopefully get that done by tomorrow night!

[aussieghostrider]

yeah sounds like the coolant temp sensor to the ECU

theres 2 coolant temp sensors ..the other goes to the cluster ... one goes to ECU which kicks the fan on when engine is around 1/2 to 3/4 hot ....

[justice4all3000]

I changed the sensor yesterday, so far so good! I'm going for a long drive tomorrow so we shal see if the $20 sensor was worth my money