Knocking at WOT, in 3rd gear, above 4k RPM

[ibismojo]

I'm stumped here. I've replaced my fuel filter, I replaced the hi/low fuel pump relay. The weather was 55F out, my tune is stock (I had a Ford dealership check to make sure it was). My pulley's are stock. My intake and exhaust are stock. Everytime I get past 4K RPM in 3rd gear, there's knocking. On warmer days, there will be knocking at the very top of 2nd gear. I had my truck dyno'ed 5 months ago and the tail pipe AFR reading was 12.78. The truck made 363 hp, 422 tq. Weather was 74F. And that was before I changed the fuel filter.

What am I missing here? The knocking went away when I dumped some 100 octane into the tank for a 94 octane mixture. It can't be just crappy gas, I thought these trucks were tuned rich for 91? :??:

 

[Scuba-Matt]

Is your inter cooler pump working?

 

[SWThomas]

Clogged injector(s)???

 

[Eds01Lightning]

Carbon build up maybe?? Run a bottle or 2 of Techron thru your tank.

 

[busakiller]

The knocking went away when I dumped some 100 octane into the tank for a 94 octane mixture.

you just answered your own question. start filling your tank somewhere else. i like chevron and shell.

 

[castellscl]

The cheapest gas price in town isn't always the best price for you pocket book in the long run.

Try a new gas station.

 

[bgstew6]

+1 to checking your IC pump to ensure it is working

 

[ibismojo]

I usually fill up with Shell. I've tried a couple different gas stations with the same result (Mobil, Chevron, 76). I'll check the intercooler.

Is there a way to check to see if the injectors are clogged? I've ran a bottle of gumout through it but still no dice.

 

[13 Z]

Check to make sure the noise isn't coming from your S/C. My eaton started making funky noises. Come to find out it was getting ready to die on me.

 

[ibismojo]

Intercooler's working.

I took it to DMP and it read 12* when it started pinging. Sucks. At this point, it's seems like crappy CA gas is the culprit. Guess I'll just keep it under 4k until I get a tune.

Thanks to DMP for their help though.

 

[LightningClint]

I have never had a problem with the gas out here and I only use Chevron

 

[ibismojo]

What year is your truck? Is the engine stock?

 

[2tonOfun]

how many miles are on your plugs?

 

[ibismojo]

Just changed them out 1000 miles ago.