So on my 06 G35 AT sedan since I bought it last month it’s had sluggish acceleration under 2k rpm, When under 2k rpm I have to be very gentle with the pedal, And when accelerating under 2k rpm the engine sounds like it’s whirring and most of the time I hear a fast tapping/creaking sound coming from the front of the car (also when idle it sounds more like a tapping) . once it hits 2k rpm it feels like it shifts a little rough and the rpm’s go back down to around 1200 after that it accelerates a little better unless I come to a stop and accelerate again it goes back to being really sluggish. And if I accelerate to 2k rpm without going past it and let go of the pedal the car jerks forward a bit. It also jerks forward when coming to a stop unless I apply the brakes really hard. I get very terrible gas mileage as well I get maximum 200 miles per tank. If I accelerate fast past 2k rpm the car feels fine and on highway I get no issues runs very smooth I’ve even gotten it to 120mph on a empty highway late at night. It’s just the sluggish acceleration. Oh and it has no check engine light no codes I had it scanned at a mechanic when I took it in thinking it was the tps but he said there were no codes. I use the correct fuel too. Is there anybody who can help tell me where to start? I really love this car been my dream car since I was 16

 

Could be a few things.


But firstly, have u checked the condition of the spark plugs?

 

I'd suspect a big vacuum leak, definitely need to pull and inspect the plugs though.