Slight Idling Issue

[Mayuri Krab]

Hey guys, as the title says my car is having a slight idling issue.

1st of the Car is a very stock R33 GTS-T auto, only mods worth mentioning is the BOSCH in-tank fuel pump that was fitted when my stock one died a while back & some unknown brand fart cannon.

The problem is, while the engine is warm, every time I start the car up (like turn the engine off & restart it), the car idles low (rev meter reads just over 500rpm), if you put you hand on the steering wheel, you can feel it shake a bit every couple of seconds and every time it shakes you can hear the exhaust sort of like "coughs" but I don't see any fluctuation of the rpm.

This only occurs when the car is completely stationary, once it gets going all the above problem disappears, & the above problem will only last for about 3minutes or so. IE if I drove around for a while and stop at the next set of traffic lights, all the idling problem disappears, idle rev is back to ~750rpm (which I read from another post is the correct idling rpm for a stock car), no steering wheel shake or exhaust "cough".

And the problem will not return (I once waited in line at a petrol station for a good 10 minutes or so & it was idling fine) until I turn the engine off & restart again (provided the engine is still warm) then it will do the whole problem again & then the problem will again disappear after a couple of minutes.

Other than that, I haven't notice anything else wrong with the car, the idling issue doesn't seem to be causing problems for anything else, my fuel economy is still about the same (11L-15L/100km), acceleration still feels the same as before etc etc.

I did a bit of search on idling issues & came up with the AAC valve thing getting dirty causing idling issues. Could anything else cause the above problems?

I'm going to Hyper Drive hopefully after the Uni exams (2wks time) to get a turbo back exhaust fited & a boost gauge installed and seeing how I'm completely useless at any kind of mechnical work I figured I'll just pay them to clean the AAC valve thing for me.

So I was wondering if people can add any other potential thing that could be causing the above problem so I can add it to the list & get them to check/fix it as well.

Thanks