what can be causing this throttle problem /loss of power

[G35-31]

i just swaped my non rev motor for the REV UP motor and now my idle when i start up jumps by its self to 2k and then goes down between 1k and 1200 when i get on it car feels like theres something holding it back but i get the same thing, power while crusing it stutters i can get off the gas and the idle will stay there at rpm's, i have tried to reset the ecu by having it unpluged for over 5 hours but still same thing,can anyone shoot me some advise?

[Tollboothwilley]

O2 sensors. non-rev/rev-up are going to be different.

My guess is that you have narrow band and the REVUP uses the WIDEBAND.

[G35-31]

i just switched out the o2 sensors today because the narrow ones didnt connect , these are now 6 prongs the narrow are 4 prongs

and nothing changed

[G35-31]

coulds this be a bad ecu unit?

[Tollboothwilley]

Have you checked your fuses? Have you done : throttle close position relearn, idle air volume relearn, and ECU reset?

It sounds to me like your idle is off for the throttle body. This can happen when the throttle is disconnected and battery is connected.

[Tollboothwilley]

Timing is extremely critical. If it is NOT DONE within the specify time, the ECU will not reset and the Check Engine Light (CEL) will continue to remain ON.

ECU Resetting Operations Procedures

1. Confirm that accelerator pedal is fully released, turn ignition switch “ON” and wait 3 seconds.
2. Repeat the following steps (2a and 2b) procedures quickly five times within 5 seconds.
2a. Fully depress the accelerator pedal (HARD).
2b. Fully release the accelerator pedal.
3. Wait 7 seconds, fully depress the accelerator pedal and keep it for approx. 10 seconds until the CEL starts blinking.
4. Fully release the accelerator pedal (while the CEL is still blinking)
5. Wait about 10 second.
6. Fully depress the accelerator pedal and keep it for more than 10 seconds.
7. Fully release the accelerator pedal (The CEL light will continue to blink).
8. Turn ignition switch to “OFF” position and now you can start the car. The CEL light should be gone.
If the CEL light continues to remain ON, repeat the above steps. Timing is EXTREMELY critical to resetting the ECU.

Accelerator Pedal Release Position Learning
Operation Procedure

1. Make sure that the accelerator pedal is fully released.
2. Turn ignition switch “ON” and wait at least 2 seconds.
3. Turn ignition switch “OFF” wait at least 10 seconds.
4. Turn ignition switch “ON” and wait at least 2 seconds.
5. Turn ignition switch “OFF” wait at least 10 seconds.

Throttle Valve Closed Position Learning
Operation Procedures

1. Make sure that accelerator pedal is fully released.
2. Turn ignition switch to “ON”.
3. Turn ignition switch to “OFF” wait at least 10 seconds.
Make sure that the throttle valve moves during above 10 seconds by confirming the operating sound.

Idle Air Volume Learning (Throttle Position Learning)

It is better to count the time accurately with a clock.

1. Perform “Accelerator Pedal Released Position Learning”.
2. Perform “Throttle Valve Closed Position Learning”.
3. Start engine and warm it up to normal operating temperature.
4. Turn ignition switch “OFF” and wait at least 10 seconds.
5. Confirm that the accelerator pedal is fully released, then turn ignition switch “ON” and wait 3 seconds.
6. Repeat the following (steps 7a, 7b) procedures quickly five times within 5 seconds.
7a. Fully depress the accelerator pedal (HARD)
7b. Fully release the accelerator pedal.
8. Wait 7 seconds, fully depress the accelerator pedal and keep it for approx. 20 seconds until the Check Engine Light (CEL) stops blinking and turned ON.
9. Fully release the accelerator pedal within 3 seconds after the CEL is ON.
10. Start engine and let it idle.
11. Wait 20 seconds.
12. Rev up the engine two or three times and make sure the idle speed and ignition timing are within the specifications.

[Shakuya88]

High idle, surge on start....Check for vacuum leaks, I had the same issue before. Did you remove any intake components after the throttle body? Check at those first.

[G35-31]

Yes took top manifold offf from bottom piece,I left my neg off the bettery for 16hours lastnight got up this morn started up and nothing changed when I drive it's like my throttle get stuck ,I'll be off the gas and for like a second the throttle won't let off it stays where I was crusing at

[Tollboothwilley]

I know i've said this but...

ITS YOUR IDLE. RESET THE IDLE VOLUME via the procedure above.

I've had that issue. When I cleaned my TB it did the same thing. I had to replace my throttle body.

When you let off the gas the rpms kind of bounce right? Idle drops to 1100-1200 and nothing lower.

If you have a plenum leak you idle will DROP. Leak = lower vacuum pressure = lower idle = engine starts to stutter and can die.

[G35-31]

Yea it jerks the idle,but would this cAuse the car to lose power?

[iiiJEFFiii]

I actually just saw a problem like this on my friend's 350Z. Turned out he had a bad accelerator pedal position sensor. Replaced the accelerator pedal assembly. Also, his "service engine soon" and "vdc" lights flipped on at the same time. checked fault codes and found P2128 and P2138.

[pfarmer]

Originally Posted by G35-31

Yea it jerks the idle,but would this cAuse the car to lose power?

You could always try the reset procedure to see if it will.

[G35-31]

Ok so I did the relearn and I'm not throwing a check engine light anymore but
but car still doesn't have power when I get on it and the car jerks still WTF ?

[Tollboothwilley]

the reset didnt take. do it again...let it idle longer...idle needs to drop to AT LEAST 700.

[Shakuya88]

Since you separated the plenum, you may have a vacuum leak, which would cause the lack of power and jerking. The PCM is trying to compensate for the un-metered air (air entering after MAF sensor. From what you say it doesn't sound large. If you access to a smoke machine, hook it into a vacuum line, and see if any smoke comes out.