So weirdest thing happened today, I was on the on ramp getting on a freeway, annoying lexus driver in front was not speeding up like he should have been doing so I merged into the next lane, was in 5th gear at that time speeding up and as soon as I switched to 6th the car turned off and on within a second.

Dash lit up with the usual start up lights, navi restarted, radio stopped, tach and speedo dropped down to 0 and then back up to the speed I was driving at. I also felt loss of power at that point as I was on the gas pedal the car stopped pulling for that one second.

Freaked me out so I move to the right most lane preparing for an imminent failure but the car did not do anything after that. No CEL nothing. I did have my HIM plugged in yesterday as the Navi kept resetting randomly, there were quite a few DTC's on the Body Electrical one of which was a Communication BUS error, something to do with the power seat control and another dtc related to the right side mirror. Ran tests on seat and mirrors no issues I can see. But ya, I cleared the DTC's last night and was driving this morning into work and this crap happened. It has been hot and humid the past few days but nothing like what we are going to see today here in Toronto.

I don't even know what to search for, but I feel like I read about someone having this problem before. I really need to figure this out as its a potential safety issue.

Edit 1 : This post (https://acurazine.com/forums/3g-tl-problems-fixes-114/scary-car-shut-off-while-driving-779206/) looks like it may be related but no resolution other than battery. The TL got a new battery before I pulled the car out in May, put in a Costco Kirkland battery made by Johnson Control Inc. I do want to check the connections when I get home tonight, however even if a battery looses a connection I would think the alternator would run the car.

 

did you look at the battery terminal?
the cables must not be tight from the new battery, and the jarring ride must have momentarily disconnected the battery

 

This is identical to what I am experiencing. I pulled the battery cover off and low and behold the negative cable has build up on it and my battery tie down was not as tight as I would have liked it.

http://www.tsxclub.com/forums/1st-ge...-restarts.html

 

The car really does not 'run on the alternator'. It actually much less direct than that, the battery more or less damps oscillations, and the alternator reacts to loads. This gets all the more complicated when the alternator takes power to make power since it has no permanent magnets.

You really need a battery. If the battery suddenly goes missing, electrically speaking, its entirely possible the alternator could have a scare and not react fast enough to maintain stable running voltage.

I had my old car react how you described when I was driving around without an alternator. When the battery got low, at full throttle the thing died momentarily and then sputtered back to life after a second.

 

If you read my posts I did replace the battery when I pulled the car out from storage. Yes it's possible that battery could be bad however there is no other signs of a bad battery. Car starts strong, runs fine even with my sub blasting.

I got home and I took the negative battery cable off, cleaned it up with battery terminal and cable cleaner. Also took off the ground wire from the motor/motor mount on the passenger side and that thing is horrible. I believe this cable has the most movement when driving as it moves when the engine is rocking back and forth especially since I was pulling hard in 5th gear and switched to 6th when it cut out.

I cleaned as much as possible and put it back. I am going to look into new ground cables.

 

Sounds pretty scary. You might want to get that battery checked. I have tried 2 batteries on our 2004 TL A/T from costco after the original battery warranty went out. Both batteries had to be replaced between 10-18 months even though the car was driven everyday. After the 2nd one gave out I switched to Wal-Mart battery after finding out that most of theirs are rebranded Interstate batteries which some say is the better/best to get. Think Wal-Mart offers 3 year replacement but its been in the car now for 4+.
Also when i purchased my 2006 TL 6MT the OEM battery in it was weak probably due to not being driven often so I switched that to an Interstate battery as well. No battery problems yet going on 2+ years

 

I had the same issue a few weeks ago. I replaced the battery less than a year ago, and also had it tested and it was fine.

I took the cables off and noticed a LITTLE amount of build up inside the cable where it would be making contact with the battery terminal. I did not notice this until I took it off. Did a quick clean with a wire brush, and was all back to normal! Has not happened since...

 

ya it hasn't done it since I cleaned the cables....