Nasty knock/tick under acceleration

[USAFVMI08]

I've noticed a couple times recently that whenever I hit the accelerator between 1/4 and 1/2 throttle to merge on to the interstate that my car will develop a really really nasty knock/rattle/tick. Whenever I hear that I let off the gas a bit and it goes away. I will say that down here in TX, the only gas I can get is 92 or 91 octane instead of my normal 93 (unless some one in the Wichita Falls, TX area knows of a station that has 93 octane :D ). Is this due to the lower octane gas or is it something more serious?

The only "mod" I have is a drop in K&N and a gutted airbox. BTW, it definitely improved that spool sound/BPV sound when I did that :p

[tunersteve]

I got a bad spell of knock tonight coming home from work. Out of nowhere in 4th gear, I saw almost 11 on the knock reading from my DH.

Do you have any way of monitoring it? Keep an eye and try to log it if possible.

[USAFVMI08]

No, I've got nothing, unfortunately. There is a performance shop near me that I think has some equipment like that. If it happens again, I'll probably take it over there and see if they can hook me up and I can replicate it.

EDIT: BTW, it's an 06 MS6 Sport

[Alladin]

Read this and see if it sounds like the same problem.

http://www.msprotege.com/forum/showthread.php?t=123740481

[USAFVMI08]

Sweet. Thanks Alladin. I replied.

[gooniac33]

mine was doing this pretty badly before I changed the plugs. It says that the plugs should be changed at 45k miles and they for sure needed to be. My car doesn't have any issues anymore since I changed to the one step colder. It is stock with a K&N drop in filter and now I can get on the gas at any speed with no hesitation or knock. And I am on the pee water 91octane gas as well...

[USAFVMI08]

Yeah. The plugs will come soon. I'm almost to 45k :)

[Super Shredder]

can anyone supply a link to purchase an installation ready step colder set of 4? ones that are prepped to go directly into the mazdaspeed6?

[USAFVMI08]

http://siteground207.com/~protegeg/product_info.php?cPath=34_404&products_id=1343


IIRC, they come pre-gapped for the MS6. You might want to double check that, though.

[USAFVMI08]

Just did it again today. I had 92 octane in the tank. I'm betting that that's the cause of the knock. Too bad there's no 93 octane here in Wichita Falls :(

[USAFVMI08]

Woo! Found a place that has 93 octane (Shell)!!! Filled 'er up and so far, no problems! Looks like I'll be going there for now on :)

[gooniac33]

if you are close to 45k miles you need to get those plugs changed. Look in your manual and it will tell you that they are supposed to be changed at 45k miles. I have been on 91 octane and since I changed them there have been no more issues what so ever.

[all4bspinnin]

it sounds like your car needs a bit of TLC, i would change plugs and make sure you had a good octane in the car... you may be getting craptastic gas. Its also nice to see someone who knows to let out when the car makes an odd sound...

ive actually hear a kid say " i like the way my car sounds when i put 87 in it" (local honda guy that just bought a B18 swapped civic) ...my buddy said "umm... ya, thats detonation you retard" it was pretty funny

anyways try some new plugs and a clean filter.

[Blendercloud]

it sounds like your car needs a bit of TLC, i would change plugs and make sure you had a good octane in the car... you may be getting craptastic gas. Its also nice to see someone who knows to let out when the car makes an odd sound...

ive actually hear a kid say " i like the way my car sounds when i put 87 in it" (local honda guy that just bought a B18 swapped civic) ...my buddy said "umm... ya, thats detonation you retard" it was pretty funny

anyways try some new plugs and a clean filter.

Before doing this, I would run a bottle of Heet through the gas tank. It will help eliminate any moisture that may be in the fuel system from bad gas you may have gotten. Don't do it after you change the plugs as it has the potential to foul your plugs.

[USAFVMI08]

Just put in a set of IVT22s and it definitely runs a lot smoother. The Air Filter is practically brand new. Just dropped in a K&N. We'll see how it runs with this next fill up. :)

[USAFVMI08]

Well, it happened again the other day, twice in a row. But hasn't happened since. I'm thinking that it might be bad gas. I can't get it to happen under similar conditions (1/4-1/2 throttle, merging to highway speeds) when I try so I'm thinking the gas might have water in it. We'll see. :(