adlee3

Hey everyone,


I have a 2008 automatic g37 coupe. It drove perfectly fine for the past year after I bought it. However, about 3 months ago, my car battery died and had it replaced.

Ever since then, my car would occasionally die on me on a warm start. On a cold start, everything is fine. I would drive to a Starbucks. Get some coffee and come out, and it would die on me once or twice before I could get it too start.

Recently, after driving for about 20 to 40 minutes, my car's RPM will begin to go up and down around the 900 - 1000 mark. When I cold start my car, the RPM will be around 700 and stay steady. Shifts are smooth and I don't feel any lunging at red lights.

However, after driving for a bit. It will start doing the RPM rollercoaster at every stop sign, red light, etc. The car seems like it is revving by itself. ALSO, when I drive in manual mode, there is a bit of a time when it seems like the car is not moving even though my foot is pushing the accelerator. This occurs around the 1500 RPM. After the car doesn't accelerate for about 1 second, the RPM will jump to 2 and everything is normal and smooth from that point on.

I have searched for days, and have read about resetting the ECU, idle relearning, and cleaning the throttle bodies. I did reset the ECU about 2 times and nothing has changed. I did not clean the throttle bodies, but thought that it should have been done awhile ago. And all of these problems didn't start until after the battery was changed.

Has anybody experienced this? Please Help. Thank you in advance!

adlee3

Update: so after reading more, I was convinced that I needed to clean the throttle bodies. I was about to do so, and couldn't get the screws to budge using an allen wrench. thus, I couldn't get to cleaning the throttle body.

I went to a nissan dealership because there is no infiniti dealership within 250 miles of where I am. They told me that they weren't allowed to clean the throttle bodies and said if they couldn't fix my problem with the idle relearning procedure, i would have to get the throttle bodies replaced. and that would cost 500+

My new question is, do you think my problem is actually because of the throttle body? i wouldn't want to have them replace it and then still be a problem and waste 500+ dollars. they also wanted to charge me 100+ to diagnose the problem and do the idle relearning procedure.

jaykellogg

I replaced the battery in my 350Z and I had the start up stall happen. It didn't happen often and I got rid of the car before I figured it out. In 2 months or so it never relearned and stopped doing the stall. I didn't have the rolling idle you describe. If you can get to the throttle bodies I would spray them. You may have to pile rags or a tray under the TB so when the solvent runs out it gets caught. I doubt I would take it to the Nissan dealer, they do not seem to know what to do. Make sure there are no air leaks in your intake.

jaykellogg

Have you got a service manual? Have you performed the Throttle valve closed position learning? Have you performed the Idle air volume learning? How about the Accelerator pedal released position learning?

JerseyG37s

just a word of advice for you...if you take those throttle bodies off and you move the flapper even slightly you will need to replace them.... try bringing the car to infiniti i know its a long drive but if you cant figure out whats going on they will.....you may also need head gasket seals since my 2008 g coupe was moving around 900-1000 and i did the seals all is good...that is covered by your power train warranty...hope this helps! btw theres no way youre getting the throttle bodies off with an allen wrench i had to use an impact wrench to get my off when i put my intake manifold on.

venzz

iTrader: (1)

Hey man did that happen after you cleaned your throttle body? I noticed i m having the same issue after i cleaned my TB and moved the valve. Am i boned?

adlee3

Update: So I ended up getting the throttle bodies replaced for free with warranty. However, the problem still persisted as soon as I drove out of the dealership. Does anybody have any theories to explain my problems? It seems that the dealership didn't want to waste their time trying to figure out the problem since the car didn't throw any codes out.