The old air intake filter was very dirty, so we changed it. After that we start her up and the RPM will go up to about 2.. after that it will not accelerate. The car will stay on and idle fine though.

What could this be? It's an '03 Coupe A/T.

Does anyone know where the throttle is located so I could check it out?

 

Have you tried resetting the ECU, peddal position and throttle valve? There is a peddal technique for this. Or you could simply disconnect the negative battery terminal and pump the breaks a couple of times to release enegy. You could as well leave the negative terminal disconnected over night. See if that works once you hook it back up.

 

How do I reset the pedal position and throttle valve? I just disconnected the negative battery, pumped the brakes, and it's still the same.

 

The procedure is on this forum somewhere, check the DIY section. I just disconnect the battery when I want to reset everything.

 

ECU Resetting Procedures

This link was provided earlier for a Basic ECU Reset, but in case it's ever broken I thought a hard copy on site might be appropriate. Perhaps even a spot on the FAQ board?

http://www.technosquareinc.com/350reset.htm

NOTE: Please read all instructions and be familiar with them before any attempts. Timing is extremely critical. If it is NOT DONE within the specified time, the ECU will not reset and the Check Engine Light (CEL) will continue to remain ON. There is NO margin of error. A stop watch or an analog clock with a second’s hand is mandatory.

<u>Basic ECU Reset</u>

Operations Procedures:

1. Confirm that accelerator pedal is fully released, turn ignition switch “ON” (NOT start) 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 seconds.
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. Remember, timing is EXTREMELY critical to resetting the ECU. You may even need someone's help to do this correctly.


Note: The following reset procedures are directly from the 2004 G35 Sedan Service Manual.

<u>Accelerator Pedal Released Position Learning</u>

Description:
Accelerator Pedal Released Position Learning is an operation to learn the fully released position of the accelerator pedal by monitoring the accelerator pedal position sensor output signal. It must be performed each time harness connector of accelerator pedal position sensor or ECM is disconnected.

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


<u>Throttle Valve Closed Position Learning</u>

Description:
Throttle Valve Closed Position Learning is an operation to learn the fully closed position of the throttle valve by monitoring the throttle position sensor output signal. It must be performed each time harness connector of electric throttle control actuator or ECM is disconnected.

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


<u>Idle Air Volume Learning</u>

Description:
Idle Air Volume Learning is an operation to learn the idle air volume that keeps each engine within the specific range. It must be performed each time electric throttle control actuator or ECM is replaced, or if idle speed or ignition timing is out of specification.

Preparation:
Before performing Idle Air Volume Learning, make sure that all of the following conditions are satisfied. Learning will be cancelled if any of the following conditions are missed for even a moment.

- Battery voltage: More than 12.9V (At idle)
- Engine coolant temperature: 70 - 100 Degrees C (158 – 212 Degrees F)
- PNP switch: ON (Park/Neutral Position Safety Switch - AT only, MT fully depress clutch)
- Electric load switch: OFF (Air conditioner, rear window defogger, headlamps. Note: on vehicles equipped with daytime light systems, if the parking brake is applied before the engine is started, the headlamps will not be illuminated.)
- Steering wheel: Neutral (Straight-ahead position)
- Vehicle speed: Stopped
- Transmission: Warmed-up (For A/T models, drive vehicle for 10 minutes.)

Operation Procedure:
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. Check that all items listed under the topic PREPARATION (previously mentioned) are in good order.
5. Turn ignition switch OFF and wait at least 10 seconds.
6. Confirm that accelerator pedal is fully released, turn ignition switch ON and wait 3 seconds.
7. Repeat the following procedure quickly five times within 5 seconds:
7a. Fully depress the accelerator pedal.
7b. Fully release the accelerator pedal.
8. Wait 7 seconds, fully depress the accelerator pedal and keep it for approx. 20 seconds until the MIL stops blinking and turned ON.
9. Fully release the accelerator pedal within 3 seconds after the MIL turned ON.
10. Start engine and let it idle.
11. Wait 20 seconds.
12. Rev up the engine two or three times and make sure that idle speed and ignition timing are within the specifications:

Idle speed A/T: 650rpm, + or - 50 rpm (in P or N position)
Idle speed M/T: 650rpm, + or - 50 rpm (in N position)
Ignition timing A/T: 15 Degrees BTDC, + or – 5 Degrees BTDC (in P or N position)
Ignition timing M/T: 15 Degrees BTDC, + or – 5 Degrees BTDC (in N position)

13. If idle speed and ignition timing are not within the specification, Idle Air Volume Learning will not be carried out successfully. If idle speed and ignition timing are within the specification and Idle Air Volume Learning cannot be performed successfully, find the cause of the incident by referring to the following Diagnostic Procedure:

1. Check that throttle valve is fully closed.
2. Check PCV valve operation.
3. Check that downstream of throttle valve is free from air leakage.
4. When the above three items check out OK, engine component parts and their installation condition are questionable.
5. If any of the following conditions occur after the engine has started, eliminate the cause of the incident and perform Idle Air Volume Learning all over again:

- Engine stalls.
- Erroneous idle.

 

These procedures where taken from another thread to help out with this one.

 

Or... you somehow put it in valet mode.

 

Its already on there:

https://g35driver.com/forums/g-spot/...er-thread.html

 

You could also ask a mechanic to check your catalytic converter. I have read about people experiencing power loss issues under acceleration and the car would even seem as if it would stall. It could mean the catalytic converter is burning up from what I have heard and read.

 

Does this sound like a serious problem, this problem never occured in the 4 days that I've had it.. since we put the new filter on. Could the throttle have been messed with accidently?

 

Something could have been disconnected in the process or not installed properly.

 

I'm thinking something was disconnected because the Service Engine Light came on at the same time. What could possibly have been disconnected?

 

I disconnected the Negative battery terminal. Gonna go out again in about an hour, reconnect and see if that helped anything.

 

The filter was changed for the intake? The gas filter? Becuase remember there are sensors. Probable something was disconnected or maybe a pipe was not properly installed. Or a cap not well sealed. Maybe even a screw not tightened enough. I say have the mechanic who installed the filter recheck the process. There was defiitely something miss-done in the process. Hehe.

 

The air intake filter was changed. The person who installed the FILTER was not a mechanic, it was my boy.