Just thinking out loud.......

It sounds like you you have a bad or intermittent opening "Ground" within your electrical system. Maybe, just maybe, if you add a "Grounding Kit" it might solve the issue.

There's a DIY for making one here:
https://www.myg37.com/forums/d-i-y-i...-your-own.html

and

https://www.myg37.com/forums/d-i-y-i...und-wires.html

I've done something similar, but nowhere as involved as the first DIY I linked to. I didn't run all of the wires. I just took sandpaper and removed the paint at the three (B,F &I) fender locations noted in the first link to get a true metal to metal contact (added dielectric grease to help prevent rusting here as well) and then just ran one 4ga grounding wire from the Battery Neg to one of the bolts on the intake manifold that already had a ground wire (I think it was location E). I didn't feel the need for adding all of the wires as described within the DIY as I verified with my Fluke Ohm Meter that they were already (electrically speaking) connected. By only doing what I did, I had an Ohm reading of 0.7 when I measured from the Neg on the battery to locations F & I.

Like I said, just thinking out loud here.

 

Have a grounding kit on mine, so I know it's not that. Strangest of all, knock on wood, it's stopped being weird, it's been running fine since my last post...

 

wow I have a 2013 ipl vert 7AT and just noticed this same thing for the first time yesterday. I had drove the car earlier in the day and no issue at all. then later in the evening when we were going to dinner is when I noticed it. it reminded me of when I had a manual car and the clutch was slipping. I took it straight home and parked. I haven't started it yet so will see if still happening. Mine as abt 70K miles and has had some mods. exhaust, CAI and a flash tune but all done months/years ago. decided to check here before I took to dealer Monday.

 

Its happened twice more to me since my last post. Due to appointments, I couldn't bring it to the dealer while the issue was happening. I was able to make a video of the tach / speedo to show them the issue though. Hopefully will be able to bring it in next time.

 

speaking from experience on hondas and mercedes benz the accelerator pedal sensor will not always throw a check engine light. i have replaced plenty especially on mercedes where there was no fault codes. the internal sensors inside the accelerator pedal work opposite of each other. depending on what scan tool layout of oem scan tool you may read one going from 0-5v and the other sensor 5-0v. or it can have some sort of positive to negative reading on one sensor and the other sensor having negative to positve reading. again it does not always throw a check engine light.

 

Here is a follow-up to my post. sorry so delayed. After I had this happen I took mine to the dealer. when I started it the next day it did not happen again. Just like you guys mentioned it was intermitten. the dealer could not replicate it either so what they did was just reprogram the transmission ecu. So far still no issues. To relay some added info, a girl that works for me reminded me that she had a couple year old Nissan Altima and this same thing happened to her. they finally told her it was a chip on the transmission and was costly so she traded it for a new Maxima. So not sure if that was really the issue or just what they thought and are not sure that would have fixed it.

 

Ok. The loss of power issue finally happened when I could bring it to the dealer. My sales rep Mike was able to see me with no appointment, and immediately brought out the lead tech. We went on a test drive and the tech couldn't believe I was flooring it as there was next to no acceleration. Kept saying 'You floor an IPL for more than 5 seconds and you're usually in trouble with the law by now." We were barely hitting 40. So we (slowly) drove back to the dealer and he hooked the car up and found it was now throwing error codes. He said it wasn't before because the issue was resetting every time the engine was turned off. It turned out to be the throttle body assemblies. They both had gone bad somehow. So my dealer kept the G for over the weekend, which was fine as they gave me a Q60 as a loner! Got her back Monday and haven't had the issue since. In fact, the car feels a little more peppy than it was. It used to feel caught off guard at times when I hit the accelerator, and now it feels smooth and fast, like when she was new. So I will keep you guys posted if the problem comes back, but right now I think I'm good. This was all covered under my warranty, for which I am thankful as the TB alone are about $600 each. I included an excerpt from the invoice in the hope that it may help some of you having the same power loss issue. My warranty runs out next month so I hafta start thinking about an extension. (Or maybe that sweet Q60 they let me use...)

 

Thanks for the update. This happened to me once. No codes etc. This is 6 mos later hasnt happened again. Was after a cai install but like i said never since. Fingers crossed. What codes lead to tb being culprit and needing full replacement?

 

According to the work order they gave me, the codes were P0101 and P010B.

 

Odb2 data loggers and gauge cluster camera

 

This is so disheartening - I've had videos of this happening on my 2012 S 6MT sedan since I bought it, and have had it in twice to try to fix. Both times, they just reset the ECU and told me nothing was wrong, but also both times (of course), the issue wasn’t happening when I brought the car there.

I’ve tried idle relearns, I’ve cleaned the throttle bodies, I got new intakes, and nothing seems to make this issue go away. At times, this is the best car I’ve ever driven, but at others, it’s so frustrating that I just want to sell it - thing is going to drive me to the drink.

My warranty just expired. I wonder if I could get them to cover it anyway if this turned out to be the issue, given I’ve had it in for this multiple times in the past 30k miles.

How could I check to see if the car is throwing codes? I have a simple PepBoys-special OBDII reader, but the CEL or traction lights have never come on as a result of this issue. Would I be able to pick up these codes on something like that, or do I need something else? Before reading this, I’ve been trying to think about what my next steps might be, and may look into a way to more thoroughly data-log to try to see if I can spot the issue.

 

audiRS4ever, do you have a smartphone? I downloaded the Fusion OBD app on my iPhone and bought a compatible bluetooth OBD port dongle off of Amazon. That allows me to read and log issues/codes, clear codes, etc...it's a good, cheap tool to have.

As far as the warranty is concerned, if it was a documented problem that you complained about prior to the warranty expiring, then yes, they should cover it.

Cleaning the throttle bodies won't work. It's most likely a calibration/electronic issue possibly caused by manufacturing errors in the TPS which I believe is integral to the throttle body and can't be swapped out separately.

If you read all the posts, the key will be to NOT stop and restart the car when it happens and record the codes with your OBD program. If possible, drive straight to the dealer. Also bring up the throttle body faults as a known issue as well as the codes, P0101 and P010B.

 

Did you check the throttle position sensor and mass airflow sensor

 

Thanks for all the advice - I'll definitely look into the Bluetooth OBDII dongle as well as the app. It seems somewhat better after the dealer performed the idle relearn, although I suspect this may be more to do with the declining ambient temperatures and humidity as fall creeps in. I've noticed that this issue seems to be correlated with heat and/or humidity, potentially. Today on the way to work, it was worse than it's been since the relearn, and it's also atypically hot and humid out.

I tried plugging in my OBDII reader during this issue, and have yet to find any error codes. My friend found a place to buy a set of Hitachi throttle bodies new for ~$300, so I may just sack up and try that if this continues to be so bothersome.

I did not check the MAF, but perhaps I'll try cleaning that and seeing if that does anything for me. IIRC, there are three relearn procedures I'd have to follow up with, correct? Throttle position, idle, and something else?

Also, isn't the throttle position sensor built into the throttle body motor on these cars?

 

No just clean the sensor and throttle body