I've done some research on this topic and it seems I am not the only one with this problem. At very random moments, while cruising or accelerating, the car boggs down for a half a second but it is enough to jerk you back in the seat. I've had this problem for 6 months now and I 've done everything I saw online.
I cleaned the MAF sensor and air intake filter, put brand new plugs in, replaced the crankshaft sensor, both camshaft sensors and just recently the Knock sensor and I still have the same problem.
I have no CEL or SES lights on and I am starting to run out of ideas. Anyone have any clue on what else it could be ??? car is driving me crazy

 

Your VQ won't suddenly hesitate for no reason. Either there's a mechanical problem (as it sounds like you've already explored), or there's an issue with the software (ECM or VDC). Since the hestitation is momentary and your VQ runs normally afterwards, I'm guessing it's the latter. Does it feel like VDC is kicking in and cutting power? Have you actually scanned for ECM/ABS/BCM codes using a system like UpRev's Cipher unit?

 

Yes it feels like the VDC kicks and cutting power for a millisecond. I've scanned it with Dashcmd and Rev lite with my iPad and my garage has a Bosch Diagnostic computer. None of them pull any codes.

 

Did 03's come with traction control? If they did, turn it off & take a drive.

 

^^ yes they did. I have it.

 

Then why is the guy not driving the car? What does he have to lose?

 

i had the same problem when i had my BC cams

 

Silvertouringz, my cams are stcok. How did you fix it ?
I drove the car for 30 minutes yesterday but I couldn't the symptoms to come back. Like I said, it is very random. Next time I can reproduce the same symptoms, I will turn the TCS off and see what happens.

 

One other thought occurs: could this random issue be an electrical power issue? When did you last change your battery? Are the terminals clean and in good condition?

The other possibility is if you have an Enthusiast model and only TCS available, it could be a problem with the wheel speed sensors sending erronous data to the ECM, which in turn cuts power to prevent wheelspin.

 

does it only happen at WOT? my old 04 z would do the same exact thing, but only at WOT.

 

No its not power related. Battery is brand new and terminals are clean and tight. I have the touring version with VDC and TCS but the TCS light doesnt come on like it would if I was pushing the car hard and one of the wheels didn't have traction.
So far, I haven't had the issue at WOT, only when cruising or slightly accelerating.

 

my steering clockspring stopped working. I replaced it with a new one but i got the wrong part. We installed it anyways. Then I go cruising down the backroad, VDC kicks in multiple times and I'm driving only at around 30-40kph. After that, VDC and SLIP lights are on.

Mechanic confirms I need to reset the system's "steering angle learning" or some sheit like that. OP, give it a shot and take it to Nissan. They might be able to fix it. Would be best to have them check your VDC and ABS sensors as well.

 

How many miles are on it and was there any work done to it prior to this issue starting?
what kind of tire sizes are you running?
Sounds like cam sensor but you said you already replaced them.
What about Throttlebody and Throttle Position sensor?
An ECU relearn wouldnt hurt either.
also if you can get your hands on a datalogging tool , see what your wheel speed sensors are reading while driving.
Sorry about all the questions lol it would give us more to work with to figure it out.

 

The car has 75k and no work was done prior.
I'm running the stock 18" touring wheels with oem size tires.
Yes I replaced both cams sensors, the crank sensor and Knock off sensor.
I cleaned the throttlebody and position sensor and mass air flow sensor. Is there a way to test them ?
I did an ECU relearn by disconnecting the battery 48 hours.
I got a PLX Wiki 2 OBD but I will have to look into whether it can access the Wheel speed sensors.

 

This is the cam position sensor, i had the exact same problem in my 03. After about 6 months it died on me and popped a code for this, replaced it and havent had a problem since. Did you replace those sensors with oem or autozone parts?

 

All the parts have been replaced with Nissan OEM parts

 

hmm weird, got a friend with a Z? lol try his throttlebody

 

Unfortunately I don't

 

Ok lately the symtoms are back. I've turned the VDC off like suggested but the problem is still here. What else could it be ?

 

Try disconnecting the Yaw Sensor, its right under the ashtray in the console. Only 3 screws and 2 harness clips to get it, 10mins max.

VDC and SLIP will stay on, but those functions should stop working completely, if it still occurs, you will be one step closer to narrowing it down to the cam sensors.

Another thing id check, is Voltage, its possible that you are losing ground intermittently, causing a temporary loss of power