My truck rattles when going up hills. The higher the rpm,the more it rattles. It sounds like a heat shield shaking. Also, when I accelearate on a flat road, I hear this very light knocking sound.

Motor has 190 000 km and is due for an oil change. Spark plugs and plug wires have been replaced. Engine sounds good when I rev it. No abnormal sounds. So, what would be my issue? Carbon build up?

 

Try a tank of higher octane fuel (89). Also some engines have a knock sensor if yours has one that could be the cause.

 

Allright, I will try that. Where is the knock sensor located and is it expensive?

 

Allright, I am gonna tank some 91 tonight and see if that fixes the rattling sound at high RPM.

If that is the fix, that means my motor is gummed up with carbon and such. Is there any motor cleaner I can buy that I can supply dump in the gas tank? I really don't feel comfortable using see foam. I've never done it.

 

Not real hard you can even search youtube and see how it's done. personally I wouldn't waste my time on that stuff. call a local GM dealer and see if they stock Top Engine cleaner, similar stuff but way better.

 

Allright, so I would simpy put that in the gas tank?

I could find this at a Ford dealer you think?

 

I pumped some 91 last night. The pigning seemed to have stopped. While I was pumping, I saw that Petro-Canada had some 94 with tactrol which cleans while you drive. I might try that next tank. Now, I have to hunt down some system cleaner.

 

my truck with a 3.0 will get to pinging slightly. I will bump up an octane grade for awhile and it goes away, after 3-4 months I have been able to put reg octane back in again. Its looking right now like its almost time for a bump up in octane again as the summer is coming in and makes it worse.

 

No you get it in a can and connect it to a vacuum line, shut the engine off let sit for 15 minutes then drive the hell out of it. I have no idea if Ford sell this or not. If you want a good cleaner to put into the gas tank look on ebay for BG 44k, a good second best is Techron.

Top Engine Cleaner
Bg products 44k performance enhancer cleaner | eBay

 

Well, that is very interesting. I did try my hardes to make the engine ping today. Drove a little hard in big hills. The motor sounded pretty good so the Premium gas seems to be the trick for that. After that, Ima go back to regular. If it persists, I would like to try that 94 with Tactron. Dont' know if that is bad for the motor tho. Would like some input on that.

Thanks for the links, but those products don't ship to Canada. I will get some GM Top Engine cleaner. Hopefully I can find. Or, if I know someone going to the U.S. soon, I'ma ask him to get me that Chevron stuff.