hi y'all - my 2016 4Runner seems to be sluggish at lower speeds and RPMs, most notably when I accelerate and decelerate. At highway speeds everything seems ok - I can accelerate to pass someone or something like that, but when I'm slowing down to stop at a light or stop sign, there's a point when, instead of coasting normally, it feels like there's more resistance than normal. And then on the acceleration, it feels like you have to press the pedal a little more to get it to go, initially.
I know it's not a race car, obviously, but I'm not sure if it's a transmission problem or fuel system. I put some Royal Purple in it, but doesn't seem to have helped. And I noticed on my scan tool that the long term fuel trim on bank 1 is around -4 to -5, and on bank 2 it's around -7. I don't know if they're related, but possibly? Really hoping it's not the transmission. It seems to shift ok and all that, but I'm not sure.
I'm going to be taking it to the local Toyota dealership Friday for them to look at it, but I thought I'd post here and get some opinions.
As always, thanks in advance 👍🏼
Mileage? Any codes? When was the last time you had it tuned up?
Sorry, forgot to include that - 95k on the mileage and no codes. Just had new timing chains, fan belt, and spark plugs put in.
Was the engine sluggish before the timing chain job?
I honestly can’t remember - but I don’t recall that being the case. I’m the second owner, so I’m not sure if it was abused before, either. The shop said it looked good otherwise.
Well it's running rich and they actually will be sluggish if they run rich you might try cleaning or replacing the mass air flow sensor
Thanks Scotty, I’ll give that a try 👍🏻
Definitely looks like cleaning the MAF sensor helped. Air filter looked ok. Here's a video of the fuel trims after the cleaning - https://youtube.com/shorts/gTDFpZ2Iy10
They're still not perfect, but definitely much better. The short-term trims are still a little above 0, but looks better. I'm curious though as to why they change so much when putting it into different gears. I included gear shifting in the video. (Haven't driven it yet to see if it made any difference with the sluggishness.)
Taking it to a dealer is a mistake. They will find all kinds of things wrong to get more money out of you. The fuel trims are showing rich like Scotty said. A new air filter and a clean MAF sensor is a good start.
Ok sounds good 👍🏻 Thanks
Just had new timing chains, fan belt, and spark plugs put in.
Why did you have the timing chain replaced at 95,000 miles? Any symptoms?
I was hearing a noise that didn’t sound right and the mechanic said there was some kind of problem with the timing chains rubbing on their cover and needed replacing.
Did you try contacting Toyota for warranty help? A 6 yr old low mileage 4Runner with timing chain trouble is not something I would expect, unless the vehicle has been severely abused. Anyway, are you certain the timing job was done correctly? Have they provided you with warranty on their work?
Maybe they skipped a tooth and the cam timing is retarded now???? A couple of degrees off wouldn't be enough to cause interference but certainly enough to throw off the compression cycle.
They did give me a warranty for the work they did - 3 years/36,000 miles. I mentioned above I was thinking of taking it to the local Toyota dealership to have them check out the fuel system, maybe I should just have them check the chains too? Or, if anyones in north Texas and has a mechanic they’d recommend, I could take it there lol.
If you’re near Dallas - https://carkiller.com/scottykilmer/qa/honest-mechanic-2/
Yeah I’m only an hour and a half from Dallas. I’ll check it out! Thanks 🙏🏻
If the new diagnosis points towards a botched timing chain job, get an estimate for the repair, but take it back to the original shop and make them fix it right. All the best!
Will do - thanks a million 👍🏻
Looks like cleaning the MAF helped with some of the long-term trims. Any idea why the short-terms bounce around, especially when putting it into different gears?
What’s the MAF reading when you’re in D with the AC off and just idling (foot pressed on brake)? It should be approximately equal to your vehicle’s engine capacity. Regarding the fuel trims, yeah it’s still running very slightly rich. But bank 1 LTFT is slightly richer than bank 2. Maybe try running a good fuel system cleaner a few more times and check the fuel trims each time. The STFT bouncing around is normal, due to a change in engine idle speed from P to R to N to D - https://www.autosuccessonline.com/understanding-fuel-trim-theory-and-operation/
Ok cool, thank you. Very much appreciated 🙏🏻
Have a compression test done. Avoid the dealer like the plague.
When I take it to the place that was recommended I’ll have them do that for sure 👍🏻