Throttle Surging. 2017 V6 TRD 4X4 Off Road package 31,500 miles (aprox)

What the OP described sounds like normal behavior on a vehicle with an automatic transmission. When in D or R with the brake applied, the engine has a load on it because the torque converter is converting rotational energy into heat and that reduces engine RPM. When you release the brake or shift to N some or all of the load is removed and the engine RPM rises.

Engine RPM can change because of changes in load, not just changes in throttle.

Additionally the cold start high idle behavior might be at play here.

In any case, it sounds normal and just something to adjust to.

 

Could also be the a/c compressor cycling normally based on this description. Try turning off your a/c and turning off the windshield defrost and see if it still does it.

 

I haven't logged in to this site for years but had to respond to this one. I have a 2016 SR5 that developed the same problem as yours at about the same mileage. Mine would surge while trying to back my boat into the garage at idle speed. There is a TSB for this exact issue for 2016-2017 models covered under the 8 year emission warranty. It is a software update TSB-0125-18 titled Engine Idle Surge With Steering Input and solved the problem.

 

Mine does not do any of that surging anymore after cleaning the throttle body. It will do a minor surge related to the AC being on, or the ventilation in the defrost setting.

However, that is a condition where it goes up to say 900 rpm, sits there for some seconds, then drops back down when the compressor turns off. Then back up again when the compressor kicks in. All of this while stopped, or parked.

The condition I had was a constant fluctuation, from 500 to 900 rpm repeating up and down every 1 second. Like a poorly running engine, which was the case until I cleaned the throttle body.

So it was like putting your foot on the gas pedal to 900 rpm, let it off, and immediately put the foot down again. Then repeat this every second for a full minute. That was the stage it had progressed to.

I have not had any fluctuation in idle now in 2 months, whereas I was getting that other condition a few times per day and getting worse by the day. It is rock stable now.

I had changed plugs, put in a new air filter, and cleaned the MAF, even bought a new MAF. None of that had any impact on the condition. The throttle body was the last thing I tried, and I did that a few weeks after having done all that other work. Gas was not an issue, I always use Chevron 89 octane and that has not changed.

 

Buddy had exact same symptoms on his Mitsu RVR with about 140k km, Idle flactuated ~500-850 RPMs. We cleaned his TB, smooth as butter now.

Cleaned TB on my taco at around 50k km as preventive maintenance, it was pretty dirty. Truck runs the same as it did.

 

How do you go about cleaning it?

 

I’ve used this guys advice, worked great.

https://youtu.be/3B-a8WJtd8w?si=9RK8Xh4Oo6gVhgyM

 

I followed this same procedure. Quick and simple and worked like a charm. I am going to clean mine twice per year now as maintennce.

 

Thank you for posting this