3.4 low rpm uphill engine ping

As the title says my 3.4l has a pretty decent ping when i start traveling up decent size hill, but still in Overdrive at a low'sh rpm. So after I press the gas to compensate for speed loss, but before the downshift occurs. Once the engine downshifts the sound is gone. The engine has 150k on it.
If i had to guess it is pre-ignition pinging. I do run 87 octane. I have read generally speaking a faulty knock censor would cause this, if so would check engine light come on for that? No light, so ignition timing possibly?

 

some things come to mind

does you engine have an EGR valve? If faulty possibility for pre-ignition.

take it out of overdrive

run better gas

check OBDII for pending codes

assuming stock size tire/wheels

 

How old are your spark plugs? Spark knock sounds just like pinging (pre-detonation), if they're old and in need of changing that might solve your issue.

 

It is not the knock sensor. Don't bother with it right now. Rumor has it the knock sensor doesn't affect timing below 3k RPM. You'll get a code if it's knock sensor and will retard timing and dump fuel. You'll know.

It's strange that your NA engine is getting this ping. You must have something going on. So here are a few suggestions:

You have a crap ton of carbon inside your cylinder and it's creating a hot point. Possible remedy- Ferrari tuneup (seriously) or at least redline your engine through a couple shifts several times. This should clear out the excessive carbon, if any. Some people will say Seafoam, and it does have it's merits, but try this first.

You're running the wrong spark plugs and creating a hot point. You want Denso dual tipped plugs.

You had a timing belt installed and one cam is off a tooth or two creating a timing advance situation. Timing belt done recently?

Is your truck EGR equipped and is it hooked up and functioning properly?

You truck is designed to run on 87 octane, and should run fine on it. People might tell you to run better gas (89 or 91), but this is not correct, you have a problem and need to figure out what it is.

Have access to a OBD reader that can read fuel trims and timing advance? Let us know.

 

You have a crap ton of carbon inside your cylinder and it's creating a hot point. Possible remedy- Ferrari tuneup (seriously) or at least redline your engine through a couple shifts several times. This should clear out the excessive carbon, if any. Some people will say Seafoam, and it does have it's merits, but try this first.It's been going on for as long as i can remember but rarely, i just started a new job a few months back though that has the perfect hill to make it do it so i have just noticed it everyday now. But anyway I red line it here and there so don't think that's it. But will give it a shot.

You're running the wrong spark plugs and creating a hot point. You want Denso dual tipped plugs. Have dual tipped, i think Denso, plugs in. I got the part number off Tacoma World if i'm not mistaken. They probably only have 5k miles and the problem was present before.

You had a timing belt installed and one cam is off a tooth or two creating a timing advance situation. Timing belt done recently? No timing belt done

Is your truck EGR equipped and is it hooked up and functioning properly? It's 3.4 so i don't believe it has one.

You truck is designed to run on 87 octane, and should run fine on it. People might tell you to run better gas (89 or 91), but this is not correct, you have a problem and need to figure out what it is.

Have access to a OBD reader that can read fuel trims and timing advance? Let us know. I don't but could maybe round one up.

 

As far as running Seafoam, just run a bottle of it with a full tank a gas?

Also just had to replace the Throttle Position Sensor and did notice that the throttle body did have some buildup. I plan on pulling it and cleaning it soon, could this possibly be related?

 

Run Seafoam through the throttle body or a vacuum line if you want to clean the TB; running it through the fuel tank is more for the fuel lines/injectors.

Be careful doing it that way though, too much too fast and you'll have a seized motor.

 

Would it serve any purpose to run through vacuum lines other than to clean the Throttle body, if not then it won't take but a few minutes to pull off and clean off the truck. 20 minutes of extra work vs. risk of seizing engine seems like easy choice.

 

I'm sure there are other benefits to it as well, people swear by Seafoam. They make a can that has a spray feature on it that makes it much safer to use that way...the regular bottle that you pour is better to put in the gas tank.

 

good luck to you. I've been hearing a ping since 2013. It's never gotten better or worse. It's just there. The manual even says you may hear a slight pinging under such conditions. I've learned to ignore it.

I tried a lot of different things that made zero effect on the ping.

 

Anyone have a solution to this issue? I just put a brand new engine in my truck and I have a very similar ping that happens in high gear/low rpm usually when pressing on the gas to accelerate up a hill or to pass someone. If I ease into the throttle I can keep it to a minimum it also fades out as speed picks up in that scenario.

Curious what sensors the ECU reads to calculate ignition timing?

How will an EGR cause this issue? Just curious to understand so I can better diagnose this issue.

 

The solution is to downshift and stop lugging the engine.

 

This problem could be related to dirty fuel injectors or fuel filter. I had the issue in a 2001 Taco 3.4l 5spd. and never figured out what it was.

 

Define Low Rpm ? To me anything below 2000 is low rpm

 

I agree that 89 octane made a big difference in my 2001 3.4l. It reduced the ping and I got better MPG, and the improved MPG almost made up for the higher cost of the 89 octane mid grade fuel.

 

I wonder does this have something to do with the different Gas blends for different states .

Seems quite a few are from California .

just a thought.

 

Some of the generic gas stations have a lower quality of fuel, so the 87 is pretty bad and who knows what they put in them to make them cost less. Then theres the whole issue of summer blends and winter blends plus states have different guidelines for the content. It takes a bit of experimenting to find what works the best. I have gotten as high as 23mpg with the 3.4l a few times.

 

Just my opinion here.
Downshift if its a manual transmission, if automatic perhaps your downshift linkage is not working right.
While I use seafoam sometimes, I do not think it will clean out the throttle body, either in the gas tank or sprayed in to TB. The only way to clean it is to take it apart and clean it. I don't think a dirty throttle body will cause pinging.

 

Just my opinion based upon my experience: why not start your troubleshooting by running your tank down and loading up a full tank of premium? Use a top-tier fuel. I personally have run nothing but top-tier, premium fuel and absolutely have NEVER. heard. one. ping.
My manual states:

Notice it states to use a minimum of 87 or HIGHER. This is a softer version of what Toyota recommends in several of their different models' manuals, including my stepson's 2010 Highlander, where they actually state flat-out; "minimum 87 octane (research number 91) but for maximum performance and minimum knock, use 91 or higher".

 

What kind of low RPM/high gear are we talking about here? For the manual trans guys anyway. If you're flooring it under ~2200 RPM in 5th gear then the issue is that you're lugging the engine