My 2003 G35 coupe 6mt has been acting up as of late. I've had the car two years this February.
Last year I noticed the car almost died when I came to a stop, it did die once, and only happens when I push the clutch in. Starting this month (January) it has started doing this again, but it has yet to die, it got close, the red battery light came on but recovered.
Currently when I start the car it idles at 1000-1100. After the car warms up it wants to idle at 100-0.
For example, I get into town to get breakfast at a gas station, I get back in my car and start it, it revs up to 1000 then drops to 100-0 instantly and the car shakes a bit, I have to rev the engine sometimes or it does die. I have attached a video showing it idling when it's warm. The car has always done this.
I have read a few posts and they ask whither or not the ac is on when it idles low, I have put both no ac, and ac on in the video.
When I purchased the car it had a piggy back mapping chip, it was causing misfiring so I replaced the spark plugs, coil packs and cleaned the maf. It still misfired and was sluggish to accelerate, so I removed the mapping chip. The car has ran perfect since then and I actually gained power without the mapping chip. I have a notepad the first owner of the car kept showing oil changes and most of the mods done to the car, although it doesn't have all of them listed. By looking at the engine I believe it has a plenum spacer, it has a k&n typhoon intake, and a lot of other mods not pertaining to the engine.
I am wondering if these two issues stem from the same problem.