spark knock at cruising speed

[Odman]

I get spark knock at cruising speed, 60 to 70 MPH in OD, with light throttle, enough to maintain speed. When I speed up it goes away, when I level out, it knocks. It also knocks under load up hill. It does not knock under load on flat ground. I have no mods. So far I've put in plugs, wires, fuel filter, used dry gas, octane boost, injector cleaner, I run 93 octane, does not run hot, I checked the valve that draws hot air from exhast manifold for cold start-up. At this point I'm stumped. I need input before I'm forced to take it to the dealer, so they can charge me $75 to put it on their scope and tell me there is nothing wrong.

 

[Sandy]

If everything is setup OK then try higher octane gasoline.

Run SUPER, my wife has the same basic problem going up hills or under load, I have told her to run Super but she never listens.

When I take her vehicle and put Super in the tank the knock goes away; of course she never notices.

This may only be a bandade for the problem but it helps.

 

[Alec]

He already said that he runs 93 octane and has tried octance booster. Most likely, you've just fouled up your injectors from too much octane. I'd go get an injector cleaning service and run 89 octane. Even with the knock, 93 is too much on a stock motor. Have you tried resetting the computer? Sometimes when the seasons change the computer doesn't adjust 100% properly and can mess up the air/fuel mixture or the ignition timing. Good luck!

 

[LStoudenmire]

Have you tried to clean the MAS(Mass Airflow Sensor) ot the oxygen sensor?