2006 M45 Sport: Loss of Power, Hesitation

[marc_m45]

2006 M45 Sport - 86,000. About 3 weeks ago I started to feel a hesitation while driving on the highway (in 'D'). Over the next few days it seemed to be happening more and more often. I decided to to replace the spark plugs (NGK Iridium) - Old plugs looked old... Car seemed to drive better for a couple days.

I took the car out of town, and started feeling the hesitation again. Finally, while going <20mph, it really started laboring, and popped the check engine, along with the SLIP. Immediately had the car picked up and taken to the closest garage (not Nissan/Infiniti). Codes came back with 'Accelerator Position Sensor' & 'Throttle Position Sensor' (did not get the exact codes from the garage). Pretty sure the tech unplugged the accelerator & throttle, performed the resets, cleared the codes, and gave it back to me. None the less, the car drove perfect again, and I drove it home 200+ miles without issue.

Now it has started up again. Exact same symptoms, but no codes. Have noticed it only does this in 'D'. While driving it in manual, there is no hesistation, but the power doesn't seem to be there. I'm looking for some suggestions.

In total, here's what I've tried/done during this timeframe:
1. Replaced spark plugs
2. Replaced camshaft sensor
3. Cleaned MAF
4. Unplugged APS & TPS, and performed Idle reset
5. Checked battery charge
6. Disconnected battery & performed Idle reset
7. Oil change
8. Added Seafoam to gas tank

[064DRSEDAN]

I have seen throttle chamber assy. fail. Especially after it has been cleaned or the butterfly has been moved by hand. It was a more common issue on the 02-06 2.5 altimas. I would advise not to buy an aftermarket rebuilt one if you decide to get one.. I know nissan offers remanufactured throttle chamber assy., I think Infinity would offer one. When the vehicle looses throttle position(built into throttle chamber) the ecm does not know how far open the throttle is. That information is shared with the tcm, and the abs/vdc/tcs system. when one part fails it can cause multiple systems to malfunction. Hope this is helpful.