I have a 2007 TCH that I purchased March 2007, I have 14K mikes on this vehicle. A few thousand miles ago I heard what can best be described as an knock in the cylinders. I did not report this to the dealer. After reading a thread on this site I tried a slightly higher octane gas, well again today I heard what can be best described as a knock. I would assume the knock sensor would kick on immediately if it could not keep up with a pre-combustion situation. This "knock" is only present when the engine is under a load, going uphill, heavy acceleration, etc. Anyone else here experiencing the same issue?

 

I had some mild pinging a few tanks ago. Like you only under a load, accelerating up a steep hill, typically speeds between 15 and 30 miles per hour. I took it to the dealer, but they took 45 minutes to come out and ride with me - after calling ahead. It barely pinged after cooling off. The hybrid tech that rode with me claims some pinging is normal.

Like you I have my doubts as that is the reason for knock sensors. Anyhow, I ran a bottle of Gumout's Regane injector cleaner in the next tank. So far I've not been able to get it to ping since. The forums on "bobistheoilguy.com" seem to think highly of Regane and Techron injector cleaner. I've got 24,000 miles on my TCH.

I don't know if I got a bad tank of gas or if the injector cleaner solved the problem.

 

I have over 34,000 miles on my car, and the ONLY time I ever hear anything from the engine is when I am accelerating a bit too fast.

All other times i hear nothing.

If I heard some knocks or a bunch of pinging, I would switch fuel stations and see if it persists, if it did I would then see the dealer.

 

Mine did that too. At the time I thought it might be some water in the tank, which is a pretty common thing here in the Northwest. It cleared up before the end of the tank, so I took no corrective action except mentioning it at my next service. Dealer found nothing. I will probably know next winter. If it comes back, I think I will put a chemical dryer, like PRIST or similar into it to see if that fixes it.

 

I noticed today that when accelerating up a hill at 10-15mph the engine seemed to knock or misfire very noticeably on my 2009 TCH, making a clicking type of noise. Could have been an issue with the engine turning off/on several times within the several seconds while the issue occurred. Rest of ride home (about 15 minutes) no other issues noticed, even while driving up hills at slow and fast speeds. Will keep an eye on. Anyone else experience similar issues?

 

One time, while driving several stories up a tight, corkscrew ramp in a parking garage in SF. Severe engine loading at slow speed produced a really loud engine knock. Kinda freaked me out a bit.

But then, the dude has a 4 year old car, with 14,000 miles on it! Gotta drive that thing. Might be bad gasoline at this point.

 

I had a similar problem during one summer. I was driving up a main overpass here in town around 28 to 30 mph. I had the windows slightly cracked to keep the car cool that night. My wife heard a multiple pinging sound echoing off the concrete bridge railing on her passenger side.

I had been using a couple of tanks of Texaco gas (86 octane) from the local truck stop. Evidently it was just a bad batch of gas. Chevron and Texaco are the same company and should be of good quality.

I switched to a Chevron station the next few tanks. It cleared up on the very next Chevron fill. I did switch to a slightly lower priced Phillips 66 station near where we buy groceries. Phillips 66 is also on the top tier gas list. Now no more pinging when climbing grades.

 

I think you have heard what I heard, McGyver. Very loud, had the music on and immediately shut it off to hear what was going on. Mine is a 2009 w/ 27k miles, so I don't think it is a break-in issue. Never heard anything like it before, but then again, my wife generally drives it and she is known to look the other way when weird noises crop up. It wasn't a normal, slight pinging, that you sometimes hear in cars going up hills (although have never heard any pinging in my TCH). This was definitely a knock. I also wasn't sure if it may have been a pickup issue with the fuel pump, since we were low on fuel (read 0 cruising miles left, even though I knew there was a good 20 miles left in the tank). However, went another 1 mile, up another slight hill, to the gas station without any issue.

Thanks for the gas tip, rburt07. FYI, I recently had issues starting my 2001 Ford F150. Just got new plugs about 25k prior (it is at 116k miles), but started to occasionally (every couple of days, more noticeable when truck was turned off for more than several hours) require three or four turns of the key before it kicked over. Read about how good Chevron Techron was. Picked up a 12oz bottle, poured it in with a tank of gas. Still had some issues while running on that tank, but once the tank was used it seems as though the problem has gone away after about a month. Definitely recommend Techron for puzzling engine issues that may be attributable to bad gas or injector issues. To be on the safe side I think I'll pour a bottle of Techron into my TCH before filling up next time to hopefully prevent any more knocking occurrences.

 

Ford service people highly recommend Techron to fix pings and hard starting and other engine problems.

I used Chevron gasoline for 10 years starting in the 80's. I remember their advertisement, that techron is in ever gallon.

Others I find that have are equally as good is Phillips 66 and Shell. Other brands owned by these same companies are Texaco, Conoco and 76 brands.

These additives are said to keep the valves clean and most important, the injectors for improved gas mileage.

Here were I live, I can buy a top tier gas for about 3 cents more than a discount no-brand station a couple blocks away.

Another product that's that can be used over many tanks is the Lucas Injector Cleaner. Their are some other gas additives that also work well.

 

there should be no "water typically in gas" here in Pacific NW. 10% ethanol takes care of that.

as of "knock". somehow, it does not sound like a knock. not under conditions described by the original poster. through yrs of DYI-ing cars, I have learned that under load noise, say, uphill and step on it, or pedal to the metal acceleration, is sign of ignition being too advanced. it sort of sounds like a bunch of beetles crunching. goes away the very moment load is removed. it is caused by combustion slightly before piston reaches TDC; as a result, piston is kicked down onto the tierod, and connecting rod between piston and tierod moves just a bit, producing noise. it is normally adjusted via retarding ignition slightly. nothing can be done on modern cars, as ignition is electronically controlled, and it has to be reprogrammed completely. mof, i had heck of this issue with my Ranger, and Ford dealership refused to fix it, claiming that even they can not reprogram timing.
another source of noise can be sticky lifters.
i am not sure how it works with modern Toyotas, older ones used to have shims between lifters and camshaft lobes. they can produce tsa-tsa noise either. Blessed be Honda that has good old adjustment bolts for this.
another source can be - poor oil quality. basically, it influences lifters and other moving parts.

hate to say this, but water pump going bad can be a source of noise. but not really load related.

at this point, personally, i'd have run a can of Seafoam through crankcase, for maybe 3-500 miles, and change oil, with flush with flush oil and good synthetic oil refill.