Engine Knock/Ping on Downshift to climb hill

2018 Tacoma TRD Sport V6 4x4 Automatic Transmission

When cruising up a hill and the transmission kicks down a gear to climb, I get what sounds like pinging or spark knock right after it downshifts for about a second. This has happened at 30mph, 40mph , 50 mph, and 60 mph. Generally happens while at cruising speed but have had it during a downshift to mildly accelerate a couple of times

I have had this happen over the course of the past month on both hot dry days and rainy 75 degree days. Engine is warm and it can happen 5 minutes after startup or 40 minutes after startup. It doesn't happen 100% of the time and some days are worse than others but I can't seem to replicate it all the time.

Truck is under warranty but given that they can't fix the misfires while cruising (thank you Atkinson cycle)..... I wanted to see if anyone else has experience with this before playing the dealer game again?

 

I have had this start recently also (67000km). No CEL either, samesies with hard to replicate.

 

I had this on days that were hotter than normal and running 87 octane. Typically after a bit of constant throttle at moderate load, then either adding or letting off. The OVT 1.05 tunes greatly lessened it on 87, where it was only happening when getting off the throttle which is a better situation in my mind. It is now gone on the lastest 2.0 tunes since the tune is better and I can get a cost benefit out of running 92. I haven't ran 87 on the hotter days that we have had, so I cannot confirm if it is good there also.


A couple things to try:

-- Be sure that your ECU is on the latest TSB version. 04A61 for 2018 ATs.
-- A Learned Value Reset can help baseline the Stock or OV tunes. It give you a blank slate for the Taco to learn and adapt to.
-- There hasn't been any running issues noted, but you might also want to check your spark plug torque? Some folks have been finding one or two loose.​

Also, I have heard pings from cars next to me on similar hot days.

 

Do you run "top tier" gas? What I mean by that is from a name brand gas station (https://toptiergas.com/licensed-brands/). I am asking because if you buy your fuel from a convenience store/no name gas station, you get whatever they have in the tank, and it may not always have the detergents and additive package in top tier fuels. This can cause carbon deposts, buildup on your valves, etc... which can contribute to pre-ignition (pinging/knocking).

You can try a fuel injector cleaner like Techron to help clear out any deposits if you haven't been running top tier fuel. If you have been running top tier fuel, you can still try techron, but the likelihood that you have deposits is lower.

I'd suggest running some mid grade or premium fuel and see if that eliminates the pinging. If not, try the fuel injector cleaner in a tank of premium fuel and burn through the whole tank before filling up again.

 

Mine did this, exact same symptoms, from day 1.
Premium gas made it go away, and now with the OVTune the premium is worth it (as mentioned by Tonered above). But like I said, tune or no-tune my truck had this from the start whenever I ran 87 octane (yes, top tier as well).

 

Reading all these replies essentially confirms again that Toyota did not tune this truck right, well essentially tuned it to eek out that extra 1% of gas mileage but drive like crap.

I notice it more running Costco TOP TIER gas. Sunoco 87 clears it up. BUT remember when people would make fun of vehicles that needed to run a certain brand gas? I do.

I am not going to make it re-learn a strategy, that's a band-aid. It has sensors, it should be able to adapt. If the knock sensor isn't feeling the misfire I can feel and also hear, yeah, it's not doing it's job (or isn't programmed to do its job)

3 months ago I was in and asked for the latest ECU software and was told I had the latest.

Not going to OV tune the truck since I have an extended warranty from Toyota. I am hoping the engine detonates itself.

Well, when I go in for my 25k service this month, I will ask them again to look into it. Maybe a sales guy will have a good day and offer me a deal that I can't refuse to trade this TRD in.

 

Most all of the fuel that I have used has come from Costco. It would be good to compare, but there is too many variables and the knocking was only on our hottest days. Couldn't really plan for it.


Funny thing, but I get more MPGs with the tune which makes more torque and the motor feel normal. Go figure? The MPG bump is enough to pay for it in about 5yrs of driving. So basically, the Toyota ECU group was smoking a lot of drugs when they slammed these tunes together?


On the Learned Value Reset, a lot of the early values were written when factory, shipping, and dealer lot porters were shuttling the Taco around, not mention anyone else that drove it before you. A large part of the values settle in within the first 20mi. I was amazed at the difference that the Reset made for me. Some really weird stuff like having the computed MPGs going from 1mpg high to within 0.2. It also changed how the tune felt. Just something to consider.


You can verify your ECU ID with the Carista or OBD Fusion apps if you have them.

 

I've now noticed my tacoma v6 auto downshifts to 4th on the longest hills with the steepest grade here very similar to what my 4.7 tundra use to in 3rd. Both trucks would climb that hill at 55-60 mph and hold at 2200 rpm. When the taco was under 1500 miles it would never do that.

 

My computer displayed MPG matches my hand calculated MPG. Funny thing is, I get AWESOME fuel economy. My long term average goes between 25-27 mpg. Best tank was 29 mpg, best 75 miles trip was 31 MPG. So essentially I've always felt bad complaining about the truck driving like shit since it is running so efficient but being told a new truck running like shit is normal, well that doesn't sit well.

I went on vacation for a week and drove a rental car. When I got back into my truck after landing at the airport, within 10 minutes of driving home I was reminded how much this truck sucks with its shit tune misfiring/surging/knocking and couldn't believe how much nicer a rental car with a 3.6L V6 GM SUV engine was. Apples to oranges SUV to Truck, but they weight about the same and have a similar displacement.

Yeah I am pretty much just a stereotypical disgruntled customer ranting on the internet at this point.

 

I always run 89 and higher non ethanol and my truck Never pings.

 

That is some crazy MPGs. It am averaging about 21 and am happy with that, being higher than normal.

But yeah, it is unacceptable that the Stock tune has to feel that way.

Good luck with the situation!

 

Same exact thing happens to my 17. The manual says occasionally knocking is normal, but it just irked me and sounds terrible. I switched to run only 91 and it took about 90% of that away. I pura vida (autocorrect changes OV to pura vida, which I’m totally ok with lol) tuned in June and haven't heard it since. So I know Toyota screwed the pooch on their stock tune. Just purely an MPG whore from the factory.

Hope my experience helps you figure yours out man.

 

Just curious, but are you not getting better MPGs on the tunes? Most seem to, including me.

I can't say that @lugnuts088 would or could get any better mileage though.

 

I love that people are putting in higher octane gas to fix a problem on a stock naturally aspirated motor that is designed to run on 87 and is far from a high performance engine.

I guess I expect too much out of my Tacoma to run on mass produced 87 octane better than a 98 Civic HX. That civic had a lean burn engine from the factory and was not picky about gas. But my 2018 Tacoma is picky. Makes sense.

 

Very true. I tested 92 a few times. Costco has only two choices, which is fine with me given the prices and quality (running as good as Chevron had). Stock it got worse MPGs and was only slightly smoother. On the old tunes, it got equivalent MPGs and a slight power bump that I only noticed when I went back to 87. Not enough to keep using it. On the latest tunes, there is actually a couple true benefits. I'm up in MPG, more than enough to cover the cost difference, and the throttle response is significantly better.

That said, the basic CR of the motor would typically need more octane than 87. The ECU controls the ignition enough that 87 is typically okay. IMHO, there is some shitty piece of code in there that doesn't control it well enough in that transient period and we get a few pings. Like I noted though, I have heard this on other modern cars that I was driving next to. It isn't just our Taco.

The funny part is that our Mazda has a 12:1 CR and runs like a champ on 87. A freaking happy little motor. They have motors running at 14.5:1 on 87 and no issues that I have seen. Just hilarious.

 

I could never achieve those mpg's either, averaging 23 mpg, but i am satisfied with the tune/performance of this truck...its very comparable to driving the tundra when empty. Towing is a different story with the taco's performance except getting 5 mpg better fuel economy while pulling the same loads.

 

That is the funny part, esp when folks say that Taco is slow. Stock, we're a tick slower than the 1st Gen Raptor and just as fast as a Tundra.

Although, that missing grunt is half of what makes the tune great. These days, I mainly live in the sub-2,500 region for normal driving and can get boogying in the lower gears while just resting my foot on the pedal. Of course, the new 7,250rpm redline is appreciated from time to time.

 

Honestly, Toyota engines just run better on premium.

My 100 series Land Cruiser with the 4.7 V8 recommends premium in the manual.

My 2007 FJ Cruiser recommends premium in the manual. What's odd is that a 2nd gen Tacoma with the same motor, the manual recommends regular.

I believe Toyota went with regular on the 3rd gen because many buyers won't buy vehicles requiring premium fuel.

 

I wouldnt say its designed for 87. The manual states "select octane rating 87 or higher"
All my japanese vehicles drove better with 89 or 91.