GenVibe - Community for Pontiac Vibe Enthusiasts

Just wondering if anyone has an insight into my problem. I've got a knocking noise coming from the engine under load above 3k rpms. I think it might be detonation, but there are a lot of other things it could be that might be worse. Also anyone have any tips on the best products to use to clean carbon out of your cylinders. I've got a pretty high milage(135k) '03 Pontiac Vibe GT. Already replaced the spark plugs with NGK iridium IX plugs did an oil change and put fuel injector cleaner goop in my gas tank any other suggestions? I also use Stop and Shop gas cause you get a discount for shopping, my next fill up I'll try mobile or shell. It'd really suck to have to pay more for name brand gas all the time though.

I have drank the Kool-Aid; try to buy only "top tier" gasoline like Shell.

Quote, originally posted by tunertype »Just wondering if anyone has an insight into my problem. I've got a knocking noise coming from the engine under load above 3k rpms. I think it might be detonation, but there are a lot of other things it could be that might be worse. Also anyone have any tips on the best products to use to clean carbon out of your cylinders. I've got a pretty high milage(135k) '03 Pontiac Vibe GT. Already replaced the spark plugs with NGK iridium IX plugs did an oil change and put fuel injector cleaner goop in my gas tank any other suggestions? I also use Stop and Shop gas cause you get a discount for shopping, my next fill up I'll try mobile or shell. It'd really suck to have to pay more for name brand gas all the time though. Fuel filter... possibly.. I would go to a dealer and have them do a driving scan.. I used to have problems like that and it was a combination of the knock sensor and the MAF sensor... ever clean or replace your MAF? O2 sensors could be going... do you have a check engine light? Poor gas as mentioned, maybe try running some dry gas (gets the water out) Cheveron Techtron is universally liked here for cleaning up the injectors..

could try dropping in a fuel filter and new top tier gas. no CEL so if a sensor is going it's not out of range yet. I could also clean the maf I read somewhere that above a specific RPM the knock sensor really can't tell that it's knock because of other nosie interference and it's over 3k when it starts up. It doesn't make any noise at start up or idle which makes me think that ruling out piston slap, rod knock, and valve tick are justified. and can also gently rev it up to redline without getting the knock.

Not sure - but does that engine have a knock sensor ?If so, you may want to consider replacing it.

Quote, originally posted by Sublimewind »Cheveron Techtron is universally liked here for cleaning up the injectors.. Like Sublimewind suggests, I would buy this stuff, add it to the tank and go from there. It is not an expensive way to start diagnosis. It not only cleans injectors, but does valves and tops of pistons, where carbon usually builds. Try it, trust me!

you have to use 91 or higher octane in your gt,,its a high compression motor and it also states this in the owner manual!!!!when i bought my used gt it had regular gas in it,,ran rough,,after 2 tanks of premium fuel it runs very smooth,,,,that pinging your getting is from the low octane,,the exact same thing happens to my wifes sienna when under load with crappy gas,,,,my opinion,,,nothing wrong with your car,,just gotta give it what it wants,,,and higher octane gas burns more efficiently,,,i got 550km on a single tank!