Damn - this is all I need now!
Harsh, metallic sound emerges from the engine. No matter hot or cold. Oil (Penrite Semi) only less than 2 months old. Coming from left side, cyl 6 area, but not g'box.
When vacuum present - press gas pedal and raise the RPM even just slightly to 1500 - it sounds like ping/knock caused by excessively advanced timing, except it isn’t. Sound disappears immediately after intake pressure equalizes - RPM steady. Even when I engage D, the sound appears for a sec.
I was wondering it could be a lifter, but then it would remain under steady RPM, not just under load.
Ideas?

possibly something to do with your injector, mabey sticky and takes it's time to get working right. Might sound stupid but it's just one thing that may cause a pinging sound if that cylinder is not getting enough fuel.

Hmmm, good point. The sound is very harsh and metallic and does sound quite like ping - for that short moment.


possibly something to do with your injector, mabey sticky and takes it's time to get working right. Might sound stupid but it's just one thing that may cause a pinging sound if that cylinder is not getting enough fuel.

Swapped injector between 4 and 6 and no diff. It's starting to sound more like valve rattle. Could stuffed lifter cause this? Wouldn't it be noisy all the time then....
Baffling!
And I need the car this weekend, or else.

If the engine has recently been fitted, check your torque converter is tight, remove the inspection plate and check the 4 bolts that hold it on, could also be the flex plate bolts to the crank as well.

The sound you describe sounds very much either like above or a big end bearing, both will make a very loud knock sound that sounds like someone is backing the block with a big hammer in time with the rpm

No engine or 'box work done recently.
I hear you and agree, but what baffles me is that it only sounds when butterfly opened until engine reaches the assumed RPM - from any RPM, not just from idle. As in, when engine under (even so light) load, and in this case just idling and opening BF only gently.
Once revs settle (to say, 1500), sound is gone completely. And yes, the rattle comes in synch with valve action, or similar.

Quess what Mrs said.....?


If the engine has recently been fitted, check your torque converter is tight, remove the inspection plate and check the 4 bolts that hold it on, could also be the flex plate bolts to the crank as well.

The sound you describe sounds very much either like above or a big end bearing, both will make a very loud knock sound that sounds like someone is backing the block with a big hammer in time with the rpm

It may sound silly, but it could be a exhaust manifold gasket or the manifold has a hole.

If its the rear bank, use a piece of garden hose put one end up to your ear and go around the gasket on your manifold if its real loud at a certain spot have it checked.
(only saying this as its the exact symptoms I had happen on my old celica and it turned out to be a hole in the manifold)

Have checked that briefly, didn't seem to be. Will have to wait for some aid later today and we'll do proper check to try to see where the sound is coming from.


It may sound silly, but it could be a exhaust manifold gasket or the manifold has a hole.

If its the rear bank, use a piece of garden hose put one end up to your ear and go around the gasket on your manifold if its real loud at a certain spot have it checked.
(only saying this as its the exact symptoms I had happen on my old celica and it turned out to be a hole in the manifold)

Big end bearing, possibly broken big end bolt. Had the same in a Sigma, no load on the bearing and the engine sounded fine, put your foot down and it rattled heavily. Finally let go altogether and threw a piston, in bits, through the side of the block. Autopsy showed one of the rod bolts had snapped a while before the detonation. MY ADVICE = DON'T DRIVE IT!! (Or take your credit card and mobile phone with you for a tow truck)

The garden hose or big screwdriver between your teeth is a good way to locate the source of the noise. Shouldn't be too hard to localize! lol

Ok, had first proper look with my Bro. Takes 2 to check this cos cannot reach throttle while bending over to listen to it properly.
And it really IS silly, that the gasket is the fault (but reliefing). Surprised how sharp the sound is, but considering it is the exhaust bang, I guess it's no wonder. Had to order (!!) new gaskets in and will get them tomorrow at earliest. And most likely case put to rest then.
Thanks everybody for suggestions.

Sooo, Sunshine Coast, here we come!


It may sound silly, but it could be a exhaust manifold gasket or the manifold has a hole.

If its the rear bank, use a piece of garden hose put one end up to your ear and go around the gasket on your manifold if its real loud at a certain spot have it checked.
(only saying this as its the exact symptoms I had happen on my old celica and it turned out to be a hole in the manifold)

Glad to hear it mate, it isnt that silly. Its the sound of detonation by memory.