I have 1999 GT with 110,000 miles on it. Whenever I get up in higher rpms under hard acceleration, especially in 2nd gear, my engine starts to knock very loudly. I'm wondering if a bottle of octane booster is all it will take to fix this or not. I've heard that octane booster can make you car dependent on it to keep the knock away and you have to keep using it. Any suggestions on how to get rid of the knocking?

 

Octane bootser is snake oil. It doesn't work.

If your car is knocking & not detonating, you'll need a new engine before any higher octane will help you.

Detonation sounds like BB's or pebbles in a can, not a solid knock.

 

It actually does sound more like detonation. Is there anything I can do for that? Is having detonation a bad sign?

 

detonation is very bad, or it can be

 

i guess you find a tuner to see if its going lean - actually just buy a wideband

 

Well, carbon build up can cause knocking too. You do have over 100k miles on your motor. Try running a bottle of seafoam through it to remove any carbon deposits, just might be a 6 dollar fix. If you don't know what seafoam is, do a search, youll find it.

 

What octane do you run? How long have you owned the car?

Who knows what has happened to the car in the past. Maybe someone had it tuned for 93, and if you are running 87, that would cause your detonation right there.

 

Water can be used to clean out carbon also.Just ask anyone who's had a head gasket to cylinder leak.
I haven't had to do this on my Mustang yet but I'll bet if you used a spray bottle to spray water into the intake tube ahead of the MAF it would work.Avoid getting water onto the MAF element by spraying toward the bottom of the tube instead of straight into the opening.Have someone keep the engine running using the gas pedal to keep the RPM's at around 2000-3000.This should generate high enough temps to flash the water to steam and blast the carbon from the combustion chambers.You won't hydro-lock the engine because the amount of waterwill pass right through.
Now for the warnings.
Try to keep the water off the MAF.I'm sure people have gotten the MAF wet during rain storms before,but it can't be good for the thing.
Do this with the engine warmed to operating temp so the water will partially vaporize before it actually gets to the cylinders.

Seafoam is good but isn't magic.I would probably start by using a couple of cans of regular spray carb cleaner.I think the whole trick is to get liquid something into the cylinder to flash to vapor so large amounts of carb cleaner should suffice.You can place the straw between the IAC hose and the valve itself and sprayaway.Use the throttle linkage on the throttle body to keep the engine running.This would be easier than using the water trick and would clean the IAC valve at the same time.I have done this a few times if my car starts to stumble upon start-up.It's also fun to run the neighbors crazy with the smoke.

 

okay i just had this problem this week, i used to use fuel additive like every 3rd oil change just like Octane booster ETC, well i wanted to leave those little bottles alone and let them stay one the store shelves, but i went about 15k with out anything my car would cut out on me, when i started it would give a weak start up, so bak to the stupid fuel additives, i bought gumout fuel system cleaner, and the car is running fine again!!!! ARGHHH dont use fuel additives u will become dependant! Just use mid grade gas for a cleaner burn!!!!

 

I've never heard of fuel additive dependency. I think you've got something else going on.