Acceleration Surge After about 5 mins
 

Hi Guys,

I've been driving my 370Z now for just over a month and something strange happens every day after about 5-10 mins of driving. I'ts not a problem, I would just like to understand what is happening.

I'll be driving for example about 30 MPH in 4th at a steady speed and then I'll experience a very slight increase in revs (slight acceleration) and then it settles. It lasts for about a second or two. A passenger wouldn't notice it but I feel it every day.

I've read a little about the open and closed loop feedback control for the throttle. Is this the point where closed loop takes over and there is a slight overshoot of the control system?

I did try and search the forums, but to be honest, its quite difficult to describe.

Regards

Paul (UK)

AT or MT? If its an AT it could be your torque converter doing its thing.

Sorry, its a MT.

I've noticed this same thing. It's very minor and it only happens to be once in the morning - within 5 minutes or so of my first start. I have no idea what it is.

No I have not had this happen, but I don't think I've ever been in 4th gear at 30 MPH either.

I bet it is nothing to worry about, though I hope we get an answer here.

Maybe try 30mph on 3rd and see if it reacts the same way

i notice all kinds of surges and delays..... i just take it as a sign the computer/emissions are doing what they do.

when i drive the car hard it reacts great the same every time so i don’t worry about partial throttle irregularities.

Get an OBD2 Bluetooth reader and Torque. Log the data. Then, import into excel and graph it.

Rpms, throttle position, mph, and fuel delivery for each cylinder.

Did Nissan source some parts from Toyota? :D

I kid! I kid!

I get the same thing, usually after about 5 min or so of driving.

could be an intermittent vac leak anywhere before or just after the primary O2's. The surge would be from the ECU dumping in extra fuel to try and maintain stoichiometry for the unmetered (by the MAF sensor) air it picks up.

Check for vac leaks around intake and exhaust components before and just after headers.

Might also be a clutch slip issue -- not as familiar with those problems here, so just speculating.

Any CEL light / codes?

I think it could have something to do with engine, catalyst, O2 warm up, etc. Most mornings when it is cool on my way in to work I get the slight surge at almost the exact same place every morning.

I pull out of my driveway and onto a 70 km/h flat road with no stops or turns for ~15 min with little traffic, so my throttle input is pretty much constant. If your commute has lots of stop and go or throttle changes I don't think it would be noticeable, but it is for sure there.