anyone have issue with this? when under a load and at lower RPMs (2100 or below) i hear a bit of spark knock or detonation... it is like i am running bad gas or a lower octane... but, i've put nothing but BP (amoco) Ultimate in my ride... is this normal? or am i mistaking this noise for valve train noise? maybe i need new plugs? (9500 miles on the car...i hope not)

 

I noticed this on my car when I first picked it up. It had a full tank. My guess was the dealership put regular gas in it. Because after I ran out that first tank it's been okay.

Does it do it all the time? Maybe the gas station you are buying at is selling regular in the premium pump.

 

i hear it rarely, but so far on every tank of gas... i doubt they're putting regular into the premium tanks as that would take collusion with the truck drivers... and i don't visit the same station each time...

this is really bothering me as i think it might be valve related and not spark knock...

 

yes all G35 (coupes at least) have this....at idle you can hear it knock and run a little rough...here and there...

BUT...i never had it at running speeds or under load....engine has always been smooooth....i'll pay closer attention next time i'm driving.....

 

Rather a sweeping statement for someone who hasn't heard my car run.
I don't have any rough idling or engine knock problems at all.

Echephron, are you running 91 or 93 octane? The 2 pts difference shouldn't make the car knock, you might want to try an ECU reset.

 

True. My coupe has never knocked. I agree with Patton. Reset the ECU. Maybe try a different brand of gas. My G seems to run fine on any brand I put in, but I had a 4Runner that def preferred certain brands. If neither of those things help I would take it in and get it checked. Consistent 'pinging', as you know, is not good.

 

Maybe he means that you can feel the engine in the shifter and if you let it go it will move a bit. All standards do this. The S2000 and RX8 that I test drove did it too.

 

Reset your ECU... if your getting spark knock that low the computer is giving it way too much timing, would def have the dealer check it out, or hook a wideband up to it and see whats going on, usually u dont get spark knock untill the top of the RPM band where the engine leans out some.

Pull a plug and see what they look like too.

 

You may want to try a different brand of gas. For whatever reason, cars sometimes run better on certain brands of gas.

 

These cars tend to run pretty lean below 4k rpms, and then gradually richen out up top.

 

I actually I heard mine knocking while I was driving in a parking garage over the weekend. There's not reason why any car like ours should knock. I hate it.

 

two things i've noticed... one, it only does it when it's hot out... in the mornings, i hear no noise no matter what gear i'm in or what type of load the car is under... but, when it's 85-90 degrees, it starts... second thing i've noticed is that my air filter is fubed... idiots at dealership sprayed engine bay with "shine" stuff and it's like oil... it's all in the filter, which i didn't notice until i started driving and got road dust mixed in... i'm replacing with ztube and k&n air filter this weekend... maybe air filter being clogged silly could cause issue?

as far as reseting ecu goes, that was done this weekend when i put in new 10000K HIDs... (which suck, btw...don't get them...it's like driving around with blue flashlights)

 

Shouldn't be any knock bro. I agree with the others: try an ECU reset, then a different brand of gas.
C.

 

Mine idles rough at start-up, occasionally, no matter what type of day it is.

 

took vehicle into service center... they retarded the timing by 2 degrees... (from 15 to 13) and it cured the problem... they also recommended that i run premium fuel only... i kindly informed them, for the second time that day, that that's all i had run... bp ultimate and shell vpower... this gets me to wondering if we're getting not-so-refined fuels at our stations here... since katrina, i've had thoughts that refinement has been diminished and they're just pushing out fuel to keep up with the huge american demand...