i have an 04 g35 coupe 6mt with 90k miles. Just last night I noticed when I floor it, the car hesitates and jerks somewhat between takeoff and 3k and after that seems like it struggles to keep the rpms climbing... The only engine mods the car has is plenum spacer and stillen ztube. I've already tried resetting ecu, looking for a vacuum leak, cleaned throttle body, cleaned maf sensor, changed spark plugs a year ago and put in fuel injector cleaner in the car today after a fillup... There is no check engine light on, air filter is new and car idles just fine. Also we just had a big rain here if that makes a difference. Any thoughts? Thanks in advance!

 

I literally just had this issue. Mine was my crank sensor. Swapped it out and it fixed it. I had a check engine light though.

 

I am going to try to scan with an obd2 scanner tomorrow and see if any codes come up... Hopefully it will be an easy fix...

 

With all the research I did I came to the conclusion that my symptoms were caused by either cam sensors, or the crank sensor. the cam sensors are pretty easy to DIY, and the crank sensor is even easier. There are guides on here for all of them. Good luck man. I was racking my brain trying to figure out what caused my issues, but they sound the same as yours, so hopefully you can figure it out too.

 

Thanks! Did you scan your check engine light to figure it out?...

 

at first I didn't because the jerking and sputtering got so bad that I was worried i was damaging something by trying to drive it, so after research I found that it was one of the three sensors. I replaced both cam sensors first, and no fix. Then I got frustrated and drove it at 20mph to the closest autozone and got the code read, it was a P0335 (i think thats the code) which was the crank sensor. The crank sensor is the easiest of the three. It's on the drivers side of the tranny half way between your cats and the engine. mine had a green plug.

 

Ok thanks!

 

I was just going to add that you can get to the cam sensors without removing the intake. Use s small 1/8' ratched, a ratchet extension and I think it's an 8mm socket and you won't have to remove the intake.

 

I scanned today for any codes, and nothing popped up... It might be a pending code I guess... But I'm stumped!

 

???

 

Oh, and only happens when the car is warmed up...

 

I had a mustang once that acted that way and the fuel filter was clogged. I've heard from others that there's no separate filter and that the fuel is filtered inside the tank so it's not going to be an easy thing to change if that's the issue. Ruling out everything else, if you can come up with a fuel pressure gauge and keep an eye on it somehow while your giving it throttle you can see if the fuel pressure is dropping under load. If it is, it very well might be the filter element in the tank.

 

checked for a pending code and nothing came up once again... i guess ill just have to keep driving it until the cel comes up...

 

ok pending code came up... p0328 knock sensor 1 circuit high...
guess its a knock sensor... its gonna be a pita to replace.. does anyone know the lower intake, not the lower plenum, torque specs?...