knocking when I gas it

[LETHALxLS1]

98 z28- when driving if I gas it I hear it knocking like cheap gas but I run 93 in it always. I even put some octane booster in it and it seemed to help but came back when I got more gas. I even went to a different gas station for gas. Could it be the knock sensor? if so where is that located?

[burnws6]

The sensor is either located on top of the bell housing between the engine and transmission or sumtimes it is located on the side of the engine block near the freeze plugs.

but i dont think its the knock sensor...those things rarely go bad...

[Y2KPewterSS]

You might as well throw your money in the air instead of buying octane boost sadly to say.

The knock sensors are under the valley cover which is under the intake.

Are you throwing any SES codes? If your knock sensors were failing you should have a code.

[JwMonE99]

Check your oil

[LETHALxLS1]

oil full-no codes. I thought the octane booster might make up for the gas being shitty and it seemed to until I refueled. The temp gauge says 180 most of the time but could it be running hot causeing this knocking?

[Mr. Hyde]

I'd hate to think it might be rod knock you're hearing. Does the sound rise and fall with the RPM's? Is it any better, or worse when you first start it? (cold start) What weight oil are you running? How many miles are on it? I broke a rod in my original LS1..on a simple cold start! I've heard rod knock before (mine gave no advance notice, it just let go blowing a hole in the block) and it might be thought of as engine knock when it's not severe. That's all I can think of, and I hope it's not the problem...new motors are co$tly!

[LETHALxLS1]

Well it sounds like the valves rattling like when you have cheap gas in it. Only when its in 4th and I gas it (like half throttle) its a auto. I am gonna have a guy put it on HP tuners and maybe he can address that issue.

[JwMonE99]

I have seen this a few times, what weight oil did you use last time? You might need to go with a higher weight probably a 20-50 something

[LETHALxLS1]

I use 10-40 cause I live in Fl. I think the AC compressor is causing it. The bearings are bad in the compressor and it may be putting a strain on the motor. I drove with no air today and no problems. I dunno.

[Z28_SS]

where in florida do you live???

[LETHALxLS1]

Tampa-when we gonna trade??? LOL j/k where you at?

[danziger]

Have you checked your PCV valve? Any oil in your intake? Do you blow any dark smoke when you floor it?

[LETHALxLS1]

Have you checked your PCV valve? Any oil in your intake? Do you blow any dark smoke when you floor it?

I dont know. I will check though. Thanks

[01SOMSS!]

I get that too. its almost like predetonation. when I pump chevron it goes away sometimes. When I flor it i get a bit of black smoke. what can that be?

[02ultraZ]

Could be the timing, like 01somss said predetonation. This happened in my dads car when the timing was off slightly. sounded like it was pingin from low octane fuel.

[LETHALxLS1]

It only does it while in 4th (its a a4) when I give it a good amount of throttle but not enough to make it downshift into 3rd. I can barely hear it but I am very aware and know my car.

[Z28_SS]

i live in broward, you live far as hell from me

[LETHALxLS1]

i live in broward, you live far as hell from me

I have no idea where Broward is. I thought maybe you lived around these parts. Nice car you have there anyways. Have fun!

[INMY01TA]

Run some Seafoam thru it and get a catch can.

[LETHALxLS1]

Could you tell me what sea foam is?? and do you mean catch can for the pcv valve? please explain thank you!