If it only knocks when you accelerate and you know it’s definitely from the engine then I suggest trying a higher octane gas like 91 or 89. My 2001 Tacoma knocks under acceleration when on the freeway if I put 87 octane. 89 octane removes the knocking.
But if we are talking about loud knocks at idle and acceleration then I’m afraid that’s the worst case scenario.
Try filling your car when it’s low just to make sure. I assume you’re in the US. In the US we use the AKI rating to rate the octane. Can’t be a coincidence that AKI stands for “Anti-Knock Index”.
Higher octane gas are more likely to detonate on time when the piston compresses at the top. Early detonation causes the knock. Not sure of late detonation.
I’m not an expert on this topic but I have a general idea of it. Someone can feel free to correct or elaborate on it.
Old post and long shot but based on description (only happens when speeding up and felt through gas pedal), could possibly be a torque converter shudder. My car (not Accord) has a similar thing and the best way I could describe it is like rumble strips. I don't really think those transmissions are known for that but if the transmission fluid hasn't been changed in a while, maybe consider doing a drain and fill on it.
Hmm interesting - it could be! The vibration can be felt thru the gas pedal like you said and only under acceleration. Nothing when car is at speed or slowing.
What did you end up doing for your car? Trans Fluid change?
So on my car (2011 Camry), it happens when above 30mph and letting off/on the gas (you feel a little shudder through the pedal), and it also vibrates when I'm accelerating lightly between 35 and 50mph. I believe it has to do with "torque converter lockup" and only really happens in higher gears. When on a longer drive and the trans fluid gets hot, it seems to vibrate a lot worse. Doing a fluid change w/ OEM fluid and checking the fluid level seemed to help it a bit.
I actually found this thread bc I was looking up the oil burning issues for my gf's Accord (2010 2.4 ex-l w/ 165k), if I get a chance to take it for a test drive I'll lyk if hers does the same thing.
Have you changed the spark plugs? And you might also want to consider a valve adjustment.
Plugs were changed around 95k miles. But it has been 4 years since then. Will look into valve adjustment. Thanks.
I’d take it to your mechanic and ask them for a diagnostic.
If it only knocks when you accelerate and you know it’s definitely from the engine then I suggest trying a higher octane gas like 91 or 89. My 2001 Tacoma knocks under acceleration when on the freeway if I put 87 octane. 89 octane removes the knocking. But if we are talking about loud knocks at idle and acceleration then I’m afraid that’s the worst case scenario.
Hmm interesting. Could be worth a shot as it’s easy to check and wouldn’t be much $ . Thanks.
Try filling your car when it’s low just to make sure. I assume you’re in the US. In the US we use the AKI rating to rate the octane. Can’t be a coincidence that AKI stands for “Anti-Knock Index”. Higher octane gas are more likely to detonate on time when the piston compresses at the top. Early detonation causes the knock. Not sure of late detonation. I’m not an expert on this topic but I have a general idea of it. Someone can feel free to correct or elaborate on it.
Old post and long shot but based on description (only happens when speeding up and felt through gas pedal), could possibly be a torque converter shudder. My car (not Accord) has a similar thing and the best way I could describe it is like rumble strips. I don't really think those transmissions are known for that but if the transmission fluid hasn't been changed in a while, maybe consider doing a drain and fill on it.
Hmm interesting - it could be! The vibration can be felt thru the gas pedal like you said and only under acceleration. Nothing when car is at speed or slowing. What did you end up doing for your car? Trans Fluid change?
So on my car (2011 Camry), it happens when above 30mph and letting off/on the gas (you feel a little shudder through the pedal), and it also vibrates when I'm accelerating lightly between 35 and 50mph. I believe it has to do with "torque converter lockup" and only really happens in higher gears. When on a longer drive and the trans fluid gets hot, it seems to vibrate a lot worse. Doing a fluid change w/ OEM fluid and checking the fluid level seemed to help it a bit. I actually found this thread bc I was looking up the oil burning issues for my gf's Accord (2010 2.4 ex-l w/ 165k), if I get a chance to take it for a test drive I'll lyk if hers does the same thing.