Knocking under acceleration

[mikelebo99]

I am experiencing what seems to be knocking under hard acceleration from a standing start. This does not seem to affect performance but it is rather noisy. I use 93 octane about every 3 refill. I am going to use 93 for the next couple of refills, but with gas prices the way they are, it is over $30 to fill her up. Does anyone have any other suggestions? How does this engine deal with aftermarket fuel additives?

[RoraStar96]

For best results you should always be using premium fuel. The car needs it, its not a suggestion but a requirement for an engine that has such high compression.

Might want to check yer plugs as well now if you have been doing this fuel rotation for a while now.

[ugsrich]

I concur. Premium is the recommended fuel for the Aurora. (This isn't some collusion "thing" with the "big" oil companies!) You can try to cut down on your fuel cost at the pump and get the resulting poor performance. Naturally, with poor engine performance you use more fuel to move the mass the same distance AND you foul your pistons, plugs, and valves which lessens engine longevity and performance.

You know the ol' sayin': "Pay now or pay later."

Use the premium fuel….period.

[97 silverbullet]

is it a knocking or tapping, cause there is a difference, have you had low oil at any point?, and next time you change your oil use lucas oil additive, and if your going to put stuff in your fuel use the lucas oil injector cleaner.

[dsatt12]

Could also be on the spark side of things too...

[mikelebo99]

Well I have been using premium for 3-4 fill ups now and still no improvement. I did notice that it only happens when I am making a right turn and not a left. Any ideas?

[jim56]

Originally Posted by mikelebo99

Well I have been using premium for 3-4 fill ups now and still no improvement. I did notice that it only happens when I am making a right turn and not a left. Any ideas?

My 97 has been doing that for the last 50,000 miles, and no one can figure it out. And it is getting worse. I think it is some sort of exhaust leak maybe?

[zimaad]

Sounds kinda funny that an engine noise will only manifest itself on a right turn. When you speak of turning, makes one think of steering/suspension. Sure it's an engine knock and not a CV joint popping? What about something in the power steering gear/pump? Have you had any belts/pulleys changed recently?? I know there is a Technical Service Bulletin out regarding knocking noises caused by misaligned pulleys of the accessory drive belt system.

just some ideas...

[KillerKeller_jr]

It might possible be that you have a bad CVC joint. I have had one do that on another car when it gets really bad, that is make noise from a standstill and also turning in only one direction.

[rodtice]

when I was a member of alldata I read about this happening, BTW it also happens on my 97. The culpret was the power steering lines.

there was a tsb on the fix to replace the lines with a GM replacement. Its sounds much like rod knock, but as many of others can tell you it doesn't make any difference in 50k/mi

[mikelebo99]

I have an update. It is not the steering at all. I have been paying closer attention to when the noise happens and it turns out to happen only when the car is at a stand still. I have heard the noise no matter which direction I turn, left or right or going straight. I am going to check the spark plugs this weekend.