blueridge

I have a '01 with 104K on the meter. During acceleration a hint of a pint (sounds like loud rattling) will start at 4,000 RPM and the sound level will increase as RPM's increase. This is not a new problem, just getting around to mentioning it here.

I only use Shell gas but use 87 Octane. If I use higher grade it seems to help. I've run Amsoil cleaner in the gas many times without luck, I've pulled the valve cover and it's very clean inside, changed the plugs, and run Castrol Syntec oil. The engine is smooth and quiet all other times.

Does this sound like carbon build up? Should I try a Seafoam treatment or two through the PCV, or an Auto RX application? Or could this be a valve adjustment issue?

Thanks!

blueridge

Just tried the Seafoam option. 1/3 can and I took the line off the PCV. Smoked up the neighborhood! Any opinion on a second dose within a day or so if this doesn't work? Will taking the Seafoam in via the brake booster do the same as the PCV location?

Took it for a spin and the ping is not as pronounced but still exists. I'll drive it some more and see if it clears up.

bob2200

Wow, my RX never has never seen the high side of 3,000 rpm. Maybe a lot of others have this condition and don't know it.

lexus114

blueridge, you mentioned it goes away with higher octane fuel. Try using the 89 octane,and see if that clears it up for you. I use Shell gasoline in my 01 RX as well,and it runs very well on it. Also, I have been using 87 octane since the ridiculous fuel prices hit this summer. Fuel millage is no different either, the only thing I noticed is when flooring it up some hills, I get the rotten egg smell from the cats. Other than that, try what I mentioned to you. You probably have some carbon build up,or your knock sensors are on their way out. And get yourself a can of BG 44k injector cleaner,that will help your situation as well.
rm