random acceleration issue

2019 Tundra SR
64k miles

Not even a month ago we bought the above truck for our 18yo. It came with a 12,000 mile bumper to bumper warranty and a 100,000 mile transmission warranty.

Next day I brought it to be checked by a local automotive place and all they found was a gas leak. On 08/26, that was successfully fixed by the dealership, by replacing 3 things: fuel pump retainer, tank suction tube support, and fuel suction gasket.

Son's been driving the truck since then (08/26). Last Thursday (09/12) - two times that day, something concerning occurred that we are trying to get to the bottom of.

Around 5pm, he was pulling out from his job and making a left hand turn. When each way was clear, he pushed the accelerator and could hear the engine revving but minimal movement. Thankfully, he quickly realized he needed to get off the road as there was a car coming. So, he made a u-turn back into the entrance of his work.

It happened again that night when he was leaving a mall.

Nothing before that day and nothing again since.

It's currently being looked at and as of close of business today, no codes whatsoever were showing up. They test drove it and couldn't replicate it. Tomorrow they will do a cold start test drive and some computer testing and physically look at what they think could be the issue.

When they repaired the gas tank on 08/26, could they have messed something up (fuel pump, etc) causing these two 10-15 seconds long acceleration lags last week?

I'm pretty upset about this!

Any ideas, thoughts, or similar experiences to share here with me?

 

That sounds more like a torque converter issue if the engine responds immediately but you’re not in gear/not accelerating.

 

I see you also posted in a pedal commander discussion. Do you have a pedal commander installed in his truck? I’ve heard others talk about similar issues with these types of accessories.

I have a sprint booster, similar to pedal commander, in my 6sp car and have had no issues but it could be the causing the problem?

If you do, I’d try removing that and seeing if it does it anymore.

 

Sounds like torque converter.

HOWEVER are you sure he didn't just hit the gas and it tried to do a burnout and traction control kicked in and pulled power back?

 

nope, do not have that on the car. Only reason I asked is to see if people were buying it due to the same issue. To me that would be a Band-Aid.

 

I highly highly doubt that with this particular son. With my other son, yes that would be a possibility.

 

What makes you two say torque converter?

 

If the engine revs up and the truck doesn't move then something isn't transmitting power from the engine to the ground, and that coupling from the engine to everything else happens at the torque converter. The transmission could have issue too, but in my experience it's a much more repeatable and consistent issue if it's the transmission, where as the converter can be a bit more hit or miss about when it has issues just since it's meant to slip by design where as the transmission is a much more mechanical system so it either works or doesn't.

With the truck being a 2019 it's possible the transmission/converter was overheated since it doesn't have a transmission cooler and could be the root cause, but hard to say. Hopefully the issue can be replicated. Maybe your son can try and replicate exactly what he did that day with you in the truck and see if it happens again. That's why I suggested if the throttle usage was on the higher side and if there was gravel or dirt on the road it would be easy for traction control to kick in and pull power back for a few seconds.

 

So, yesterday I brought it to a legit Toyota dealership. Want them to check and see if it needs a (tcm?) update, see if they can replicate it (the 1st place couldn't), and see what they find.

To your comments @snivilous, how much gravel on the road would it take to cause traction control to kick in? Also, don't forget that it happened TWICE within that same day last Thursday. Once when he was pulling out onto the road from his job and then again that night when he was leaving a shopping mall. Hasn't happened again since - and today's a week.

And to your other transmission/converter may have been "overheated" comment, both times it happened he had just cranked it up after work/the mall, and so the acceleration lag occurred within or less than 10 minutes of being started?

 

Oh I thought both times happened from the same location, though that doesn't necessarily weed out TC being the cause. As for the overheating I just mean it may have been overheated previously and hurt the converter or transmission, not necessarily that it was overheated at that moment.

 

re: being possibly previously overheated, like......we've owned it for a month now. how far back would an "overheating" likely cause one last week? like if it occurred a year ago w/previous owner? because we haven't driven it to the point of overheating....

also, to me it would seem like pushing a vehicle to the point of overheating would be pretty hard to do? what are some scenarios in which you could overheat a truck? (sorry if it's a dumb question)

 

Slow speed climb in 4 high does it every time.

plenty of people on here have seen the transmission temp warning at 302 - about 100 degrees hotter than it should be running. Conventional thinking has been damage starts occurring around 250+.

 

well, we had it for 3wks before it did this and we didn't overheat it. if the prior owner overheated it, would it drive fine for 3 wks and then have the issue and then nothing the following next week?

does overheating it only once create a prob? or do you need to do it a lot?

 

It’s a bunch of speculation - if both times it happened when accelerating from a stop I do think some slippage activating the traction control is most likely. The yellow light should have illuminated momentarily on the dash if it activated. I’d tell whoever is driving to look for a traction control light in the dash if it happens again.

 

Ok my husband just found this (1st screenshot) mentioning the fuel pump. As I said in my 1st original post up top (re-read pls), the dealership fixed a gas leak where also above in my post i mentioned the 3 parts they replaced. We picked it back up after repair finished on 08/26. It drove fine until last Thursday.

Here's our question:
Could they have messed something up when doing this repair to the fuel pump and that's why it lagged twice last week?

One interesting thing we found out yesterday (from the different car place that I brought it to, for a neutral party - to see what's up as I don't really trust the original service dept of the dealership where we bought it), is that when they (original dealership) put the tank back onto the truck, they somehow jammed the large tank bolt when they put it back in....where it went in crooked. Because it went in crooked, it's not flush and "in" all the way as it should be and it prob stripped the other part. See 2nd screenshot of that. It needs to be re-tapped now and put back in properly.

I don't think this wonky bolt has caused the issue, but it shows "sloppiness".

So, now our question since as of yet....nothing has been found.....could the service guy have damaged something in/around/or the actual fuel pump which caused this issue last week?

THx!