Knocking Sound at Low Throttle 2006 4.0

I have a 2006 D Cab 4.0 with 82K miles that I've owned since it was new. For the last couple of months I've noticed a knocking sound at low throttle especially after cold starts in the morning or after it is parked for a while at some place. The knocking appears when I am lightly depressing the accelerator and I hear click, it then goes away but comes back after a short period of time. I've taking it into a dealer, and they couldn't figure it out..no surprise there. I use synthetic oil on all my oil changes and fill it with 91 octane. Anyone have any ideas on this, I definitely would appreciate it.

 

If its what I think it is, that is normal for all the 2nd generation 1-GFRE or whatever motors. Mine has been making that sound since it was brand new if its the same clicking sound when the truck is in park. I was worried to about the clicking but everyone has it, even my other buddies Tacoma made that sound.

 

I purchased 2010 Taco this month & it does the same as yours at cold start-up. Sounds awful . Even sounds like a diesel momentarily when I drive off. Maybe oil is not lubing the upper portion of the engine? I don't know what it is . I notified dealer & they said there is no service bulletin for this type of problem. So they want me to leave it overnite so they can check it out on cold start-up. But they seem convinced that this is normal.

 

Clicking sound when engine is @ normal op temp. Knocking on cold start-up .

 

Yeah, sounds like the classic Tacoma ticking noise that WW_FIREFIGHTER mentioned. If that's the case, nothing to worry about. There is a writeup for a fix on this, but I can't seem to find it now, I'll keep looking and post or hopefully someone else can put up the link.
I would suggest running some SeaFoam through or any other name brand fuel injector cleaner and see if that helps. Could be some carbon build up.

Could also be some bad stuff, but I would keep doing what you're doing and if the sound gets worse and more of it. That would be a good time to take it in and they can take stuff apart and get a better look.
Next time you change the oil, try to open up the filter and check to see if you have a lot of metal shavings. You should see some shavings, but not a liberal amount.

But don't worry about it too much, should be fine. And welcome to TW.

EDIT: Here we go, finally found the link for that engine tick write-up. http://www.tacomaworld.com/forum/2nd-gen-tacomas/43632-ticking-engine-one-fix.html

 

Thanx for the info & link BakoTruck . I doubt this is similar to what I'm hearing, but I'll check out this mod/fix anyway. Couldn't hurt any.

 

Thanks guys for the info. and the link. I'll run a fuel injector cleaner through it and check out the metal shavings the next time I change the oil, which is due soon.

 

It's more of a knocking sound that appears after a cold start while first driving. The sound seems to go away after accelerating to about 20 mph. If I come to a stop or stoplight shortly after the cold start, the sound is present again at takeoff.

 

Are you running the proper weight oil? You could also send a sample to Blackstone Labs and they'll send back an analysis report (though that won't really show knocking itself). I'd think any knocking to be concerned about the ECU should throw an engine light but I don't know that for sure...

 

This kind of sound like the sound I've been expirencing for the past five months. Its pa pa pa ish sound (hard to put into type). It does it in park and then when in drive it gets louder and the when I accelerate it speeds up. When I get out of the truck and listen around in the engine, under the truck I hear nothing, get back inside there it is again. Usuall after driving awhile it goes away. I took it to the dealer and the first time they changed out the exhaust manifolds..... no change. The next time a couple months later I had a tech ride with me and he heard the noise and was baffled....???? they checked out everything engine, exhaust, driveline.... said it wasn't any of them. So since my warranty is (well thats another story)but said for them the keep looking it would cost me $$$ can't remember how much but I said nevermind so I need to go to a different dealership and start all over. So I've been living with the noise........just using the fix it all knob on the dash marked volume.

 

I also have been having this issue, mainly notice it on cold mornings and only lasts for the first few minutes of running the engine. When I barely accellerate I can hear it but at speeds above 20 it goes away. I feel that the sound has gotten more noticeable recently. Have 78k miles, and can't recall hearing this roughly <60k miles. I'm not going to waste my time taking it to the stealership, seems like no one knows the cause/fix.

 

If the injectors are dirty then the fuel won't atomize correctly and the engine will knock.

try something like this.
http://www.ntxtools.com/network-tool-warehouse/OTC-7448PROMO.html

almost every shop will have this and it should cost around $50. The products that you put into your tank is a waste of money.

Might fix your problem, might not, but it will increase your fuel mileage, make your engine run smoother, increase power.