P0300 And High Idle w/Uprev
 

Recently cleaned MAF’s and Throttle bodies along with changing out spark plugs. After clearing the code idle went back to 650rpm briefly but is now back to around 1100 with the CES light back on. Considering a flash back to stock tune but just realized I’d lose my license on the cable so not sure it’s worth trying that. Any advice?

Go through the Throttle relearn process.

Failed to mention that this issue was happening prior to the work done. I did go through the idle relearning process, but I believe there are 2 other steps I forgot to go through for the throttle bodies.

You need to make sure you do the idle air volume learning procedure as well.

Go on youtube and Motorvate. He has a step by step video on how to do the relearn procedures.

Ok thanks, I’ll do the 3 relearning processes and see if that helps. If the high idle persists would it be worth looking at a flash back to stock tune?

Any updates? I'm having the same issue (stock ECU/tune, though).

http://www.the370z.com/engine-drivet...0300-saga.html

EDIT: You're the 4th person with a 40th Anniversary (including myself) who has reported this issue. Did you have your car since new, or do you know if the previous owner had the same problem?

No update, currently trying to identify two plastic pieces that cracked so can have them replaced. I’ve had mine since around 6,000 miles and it was stock then from the dealership.

Not sure why the pics uploaded sideways lol but hopefully someone can identify those parts

Ok. Just wondering if you had been having the P0300 issue since you purchased the car.

Those plastic parts are listed in the FSM as part of the intake air ducts (see attached snapshot). If yours are cracked, I am guessing there is a vacuum leak, which could explain the misfire.

Yeah I’ve had the same misfire code on and off since I’ve owned it, but over the years it has gotten worse and now stays on.