Hey, Guys, I was wondering if you guys were able to give some pointers with this problem I'm having with my 2004 Infiniti g35 coupe. These are the symptoms when I start driving it feels like there is a little bit of drag when I accelerate, then when I'm switching gears there is a loud clacking noise coming from the engine or transmission(one of the two) and I can feel it in my clutch pedal. then whenever I'm at idle the revolutions go up and down, the engine struggles to stay alive for some reason. I have already done the idle relearn, replace the camshaft and crankshaft sensors, I put the car on coilovers, it has a high flow racing exhaust, I checked the valve timing solenoid valves, checked the brakes they were totaled fine, and cleaned the mass air flow sensor along with the throttle body. the car has been like this for a month and I have done every single test that I can think of. if anyone knows or maybe nows something that can get me closer to the answer I would appreciate it.

 

did you check the codes

 

That's the thing there are no engine codes and I drive the car for a long while and sometimes it starts to overheat

 

Just because the check engine light is on doesn't mean there's no codes.

As for the overheat, what's the coolant level, do BOTH fans turn on with the high and low speed (force it to high by turning on the AC), have you been keeping up on coolant flushes every 30k miles?

If all those things check out, pressure test the coolant system including the cap and see if there's a pinhole leak causing it to not hold pressure.