My 03 g35 with a motordyne tdx2 + art pipes + plenum spacer + nismo cold air intake seems to idle at 700 and itll drop to to 600 for a second and then run back up to 650 then back to 700.

When it gets to 600, my car shakes a bit and i can hear a misfire from the exhaust which caused me to be concerned. My mechanic said this is normal because i dont have cats. I dont experience any issues wit the drivability of the car, it feels perfectly fine and the car doesnt die or not start up or anything like that.

What idle is our cars suppose to be at? I read on some threads that my art pipes might be causing a lower idle, not sure if this is true.

I just replaced my ignition coils hoping it would fix the issue and it still has not, is this just normal for my car with my mods?

 

You can do an idle relearn after the car is warmed up. Usually a good idea after you've changed intake and exhaust components.

Should be 650 +/- 50 rpm with no load (all accessories off) and engine & trans warmed up to operating temp.

 

I do sit at around 650 +/- 50 rpm , BUT its normally at 700 and drops down to 600 for a second and my car shivers with a noticeable shake and then itll jump right back up and feel normal again.. any idea what this could be?

I was thinking maybe vacuum leak? valve cover gasket leak?

 

I think it's the idle air algorithm. You should definitely check for a vacuum leak though before doing it.

It's absolutely not "normal because you don't have cats".

 

Heres a video of it if you dont mind checking it out? I literally have on idea what to do, its so annoying sitting in a car that shakes at a red light lol

 

Try doing an idle air recalibration, steps are in the FSM section EC - Engine Controls.

If you have an Android phone you can get a bluetooth OBD2 adapter like the BAFX one available on Amazon (only one I've used, it's highly rated and works perfectly on these cars) then install the application Nissan Datascan 2 from the play store which costs like $10. It has the functionality to do the idle air recal from the push of a button instead of doing the pedal dance method from the FSM.

If you do the pedal dance make sure you follow all the prerequisite steps listed. They must be obeyed EXACTLY including things like having the steering wheel perfectly straight.

 

Personally I'd thoroughly clean the throttle body. Remove it from the car and get it really good with a toothbrush. Then do the throttle closed and idle learn procedures.

Don't be cute and try to clean it in the car still plugged in, that's how people wreck their throttle bodies.

Another sign of a gummed up throttle body is if you're getting slight surging or stutter during light throttle cruising condition, downhill on the interstate for example.