Hello all,
I have a 100% stock 2004 Nissan 350z (I think Touring trim) with the non rev up vq35.
For months, I have had a bad bank 1 (passenger) cam shaft position sensor. This would cause several things over my driving career in this car.
1 - Always takes awhile to crank and start
2 - Randomly dies at idle
3 - Will lose all power on freeway, then will spring back to life in "limp mode" with TCS and SLIP lights on
All of these are general signs of a bad CMP sensor. It was still drivable, just quirky. But since yesterday, a new symptom appeared. It bogs and stutters and flutters and hesitates when I give it just a little more than normal throttle.
This only happens when I am at low RPM and try to give it just a bit of gas. It completely freaks out and starts bogging and making a fluttering sound.
You know how sometimes when your in like 5th gear and your going kinda too slow to be in fifth, and then you give it some throttle? It will GO but its just slow and boggy and at a gear disadvantage. Well that is IMPOSSIBLE with my car. It has a fit at just the smallest amounts of throttle.
I usually start in second when at a stop sign, and I've never had any issues with it. But now, it is so bogged and stumbly I can't even do it. The car almost dies. Something crazy is going on.
It stumbles at very reasonable speeds, like 2nd gear going 30. Just a half way throttle press and it freaks out. It does NOT freak out when I go super super smooth and slow on throttle inputs. Complete baby mode.

SO, I finally got around to it and replaced the CMP sensor. It got rid of the P0340 code and all the symptoms I listed above in the list went away. Starts right up, doesn't die on idle, all the symptoms of bad CMP sensor gone.
However, the thing still ****in stutters like crazy. Completely no change.

Does anyone know wtf is going on? Anyone have any ideas? This is completely stock car, so no turbo, boost, tune issues to worry about. Only thing I can think of is a bad sensor making the ignition timing go crazy. But I haven't worked on "late model" cars in awhile. I know a lot about carbureted vehicles, not efi really.

Thanks guys, in advance!

 

Usually when one cam position sensor starts acting up, it's best to replace all of them assuming they are all original. You should also replace the crank position sensor for peace of mind. Always use OEM sensors on these engines. That's where I would start, but this could also be related to the electronic throttle body. The throttle position sensor or pedal sensor could be acting up. Having a live data capable scanner would help pinpoint the issue.

If you're still seeing odd behavior, scan the computer again to see if there's any new pending codes. I would also recommend clearing any stored PCM data since you drove the car for a while with the bad sensor. Not saying this is true in your case, but modern vehicles store/learn values for things like fuel trim and timing based on input from TPS, MAF, MAP, Crank, and Cam sensors. Modern automatic transmissions also learn & tune themselves the more you drive them.
Good Luck!
-Icer

 

Thank you for the reply! I did know about how EFI learns, and tunes fuel trim as you drive. I even pulled the battery connector off for an hour, to do a trim reset. Nothing changed unfortunately.
I bought a pack of each CMP sensor, so I have the new bank 2 sensor. Before replacing that more difficult sensor, I want to look at the throttle body and accelerator pedal. I still have no codes though, which is frustrating.

 

Double check for vacuum leaks at the intake. Make sure you don't have cracks at the intake tube and check the PCV hoses for any major leaks. Very odd that you don't have any codes given the symptoms.
-Icer