That was not the problem in my case. I replaced mine as per the maintenance schedule with the upgraded part # plugs and the problem was/is still there.

I have switched back to cheap gas and just "step on it" when I hear the detonation. If I accelerate quickly the noise goes away. The computer obviously changes the timing as it should under rapid acceleration. The slow acceleration is when the problem arises.

 

In the old days, 70's I remember some mechanics pouring water inside a carburetor as he revved the heated engine to blow out piston deposits through the exhaust. Some used brake fluid and etc. It seemed to work, but I never heard or seen it done on a injected engine.

Just a possibility you got a bad batch of gas, although doubtful after all this time. I had similar ping happen to me with the '07 TCH. I was also using a top tier gas from a Texaco station. I run the tank down to the empty mark then filled at a Chevron station for 3 tanks and the pinging was gone. That same station had put in all new fiberglass tanks only a year earlier.

I figure the Techron would help remove any moisture in the gas also adding extra cleaning to your engine. Guess not in your particular case.

 

I am still having the issue with my 08TCH at 40K, top tier gas seems to help but does not stop the issue. I had my fuel system cleaned by toyota techs after their recommendation to no avail. I am about ready to have my non-toyota mechanic look at it to see if he has any ideas! I think it might be the knock sensor like the other poster claims it might be.

 

You have used various additive to remove any possible water in the tank. Using top tier gasoline for up to 3 tanks should clean out any bad gas you may have purchased. With your TCH having such low miles at 40K I doubt the spark plugs would cause this.

Lets hope the independent mechanic finds your ping/knock problem.

 

Top tier gas is NOT the problem. I have already had my car into Toyota. The problem would not duplicate for them as it does not happen all the time. They are aware of the problem and do not know what to do about it. Apparently I am not the only one that has been in there with the "exact same problem". I have a couple friends that drive these cars. One of them has the problem. It is also an 2008 model. He runs good gas too. Always has. The problem is with the computer or a sensor. But, no codes stored. It would be interesting to have a scan tool hooked up as the detonation is happening, to see what "exactly" is happening...

I took it upon myself to have a friend run a "borescope" down the intake. The engine looks like new in there. No carbon build up on anything. Literally like new. Pretty amazing to see that with 134,000 miles.

I am heading back to Toyota tomorrow for a service. I plan to ask them about it again.

 

thanks for the post rburt07.

I have been running chevron or BP for the last 5 tanks or so, it seems to do it less than with shell, racetrac, walmart, or sams, but I can still here it. Only 1 toyota dealer actually said they heard it but didn't know what it was, keep me informed. I haven't had the time to have my independent dealer look into it yet.

 

Do let us know what Toyota has to say about your problem.

 

Here again is the toptiergas site, click retailers to see the list of quality gas brands to use.

www.toptiergas.com/

I think I left off the gas buddy site. Just below Search for Local Gas Prices type in your city, state or zip to find a 'low priced' top tier station near you.

www.gasbuddy.com/

.

 

I finally switched back to 93 octane. I am done with "top tier" and additives. Since they have done nothing and the engine is sparkling clean inside.

I had to reschedule my appt. at Toyota. I will be in there Thursday morning.

I have been doing lots of reading on knock sensors and how they can misinterpret noises from the suspension. I am hoping it is a simple "sensor" problem. I am also hoping they are able to do some "on the road diagnostics", If possible. I'm not expecting much though.

Thanks for the info. on the gas. That is interesting.

Edit:

FYI, we drive the crap out of this car. I just pulled out our mileage log (we use the car for our business). Since my last post on 9/26 we have driven 760 miles. Tomorrow and Wednesday will add an additional 300 miles. But, we still average 800 to 900 miles per week over all. SO, as you can see.... NO ONE is more in touch with this problem than I am. I need the crap fixed NOW!!

 

AJ,

Have the dealer check the static and advanced timing curves. I think the computer has learned your driving habits and has the timing advanced far enough that what you are hearing is a slight valve rattle once the engine gets under a load (going up a long hill for example). With the rattle disappearing once you use premium gas, that is a good indication. The knock sensor should retard the timing but under the conditions you describe, pre-detonation is not happening, just a valve rattle which might not be detected.

If they re-set the computer back to factory settings (basically getting rid of the "fine tuning" the ECU has done in response to your driving style) I think the problem will disappear.