Irratic Idle Issue R33 Series 2 Gtst

[Emrarrr]

Hey Guys,

Sorry if a similar topic has been covered, but just thought I would start a new thread to add more specifics etc.

I have a series 2 R33 GTST which is having an annoying idle issue. I replaced some snapped exhaust manifold bolts and there is still one snapped but meh that can wait, it isn't the cause I am pretty sure as when three were snapped it didn't idle as crap.

When idling it sounds all over the place like up and down whirring like if u imagine a police siren whirring but it's the sound of idle lol. It on occasion will also feel like it has just dropped out like it's on 5 cylinders for a split second then comes straight back. The taco doesn't seem to hunt though. It occasionally also has a weird cold start where it starts really quiet then like two seconds later bursts to life but usually starts nicely. A bit fuel smelly lately too. Anyway here is what I have checked (not much yet) and then what I am suspecting. Oh and also when I tried to adjust idle with idle return screw when I pulled the TPS the car stayed on as it should but one time when I pulled it the car died? Oh and the car gave me a code for coolant temp sensor and i cleaned it up a bit and put it back and the code went away? Sorry for the essay!

What I have checked:

Cleaned AFM

Cleaned AAC assembly- noticed an o-ring is missing and a gasket?!

Checked all hoses for vac leaks, pretty sure they ok

Checked all hose clamps etc tight through the air intake

Cleaned cold start valve

Pulled each coil pack whilst car was running- does this just check your cylinders or pretty much tells u whether coil pack is rooted or not?

What I think could be wrong:

Still some annoying vacuum leak somewhere

Throttle position sensor

Dirty throttle body

The missing o-ring & gasket on AAC/IACV assembly

AFM still- how else can I check? Resistance?

Still the water temp sensor even though code disappeared

Coil pack

Problem with the waste gate?? How can I check if it is stuck??

Anyway thats enough for now, it's doing my head in so any advice would be great!

Thanks heaps

Em

[Emrarrr]

Oh and maybe PCV valve/EGR Valve? Fuel filter?

[RamR33]

You can rule out the AFM by unplugging it while on idle and if it stalls then its good and if its still idling then its no good.

Running on 5 cylinders could be two things from my experience,either one of the coil packs is playing up or dirty/blocked injector.

If it starts to run on 5 cylinders for longer, try unplugging each coil pack to see which one makes a difference in the sound and if one of them does not change in sound or note then u found the coil pack that might be faulty but can also lead not to be coil pack but injector which you can do by unplugging each injector plug to see if it does the same thing to changing the sound.

[Mick]

i would run a bottle of injector cleaner through your car, i had a surging problem and it also made the idle a bit erratic and injector cleaner fixed it on mine, injector cleaner is cheap and its worth a try

[Emrarrr]

Thanks guys! I did the power test and all good and was actually going to run some good quality injector cleaner through maybe moly stuff in the metal can.

It's becoming so frustrating! The coolant sensor code isn't showing now but doesn't mean it's still not rooted I'm just going to replace it and see what happens. Sucks cos the car drives so nicely and I am spending half my life trying to fix this ass hole idle! Could it have anything to do with cam position sensor?? I'm starting to think cos the aac/Iavc was missing gasket and o ring then that could be a main cause? My pcv is rooted also

[Emrarrr]

I'm pretty sure it's not the exhaust gasket and missing bolt because its not the same noise etc and it wasnt this bad with extra bolts missing. When I have the money ill take it somewhere but I know I can do it myself but I need to pin point the issue first