knocking on 98 civic LX engine with 87 octane

[cvic98lx]

I bought a 1998 Honda civic lx last yr with about 168k mileage. After about a few months of driving and a few full tanks of 87octane gas, I noticed a knocking? sound in the engine (like loose metals parts shaking) when accelerating between 2500 to 3500 rpm. What I did was let the gas tank level drop to almost empty and filled it up with 93 octane gas and the knocking sound disappeared.Do I need to adjust or replace some parts on my engine (spark plugs, etc.) to be able to run again on 87 fuel smoothly? I'm still getting about 30 mpg using 93 octane on the civic and was hoping to maximize my savings if I could use an 87 fuel. Thanks.

 

[RonJ]

Bad gas or your ignition timing is off.

 

[cvic98lx]

thanks RonJ. will have the timing checked.I dont think its the gas because Ive been using the 87 on my other car with no problems at all.

 

[RonJ]

 

[HARMON]

yea, thats RonJ.... he's a genius. Dont believe me? go ahead ask him a question. lol

 

[whoopnip]

Yeah, seems like it should be timing. Our cars are tuned to run on 87 octane, so if the timing is off it might run better with a different fuel.

 

[cvic98lx]

Thanks again guys for the helpful tips!

 

[whoopnip]

Let us know how it goes! I see too many threads die after the OP fixes (we assume) the issue and then never gets back to us.

 

[cvic98lx]

had a series of diy's recently, replaced the spark plugs with ngk v power( old ones have rounded center electrodes), replaced the fuel filter (i guess its still the 98 orig filter), and the distributor rotor. i did not replace the dist. cap bec. the contact points inside still looks fine. Now im running on 89 octane. so far no knocking sound yet when accelerating. Will switch to 87 next on my next full tank.

 

[whoopnip]

had a series of diy's recently, replaced the spark plugs with ngk v power( old ones have rounded center electrodes), replaced the fuel filter (i guess its still the 98 orig filter), and the distributor rotor. i did not replace the dist. cap bec. the contact points inside still looks fine. Now im running on 89 octane. so far no knocking sound yet when accelerating. Will switch to 87 next on my next full tank.

Keep us posted.