I have a 98 Accord, 4cyl 2.3 with approximately 65,000 miles on it. The car seems to run great, and by great, I mean, it seems to not have lost any power over its years. I have noticed that during mid to upper acceleration, it will sometimes spark knock. I have not heard it during lower acceleration (0-40mph). An example would be on the highway if I go to pass a car, when I accelerate from say....55-65/70mph, I will hear spark knocking. As far as maintenance, the plugs have been replaced in the last year and a half. They were properly gapped before installation. I have not replaced the wires or distributor/cap. I purchased the fuel injector cleaner and have ran that through several full tanks of gas. It still seems to be doing it though, in the upper accel. Also, I have started running 93 octane with every fillup. Is this merely a honda thing? or possibly needs a tune-up ?

 

When's the last time or have you ever replaced the following:
- the "rotor button" (located inside of the dist. cap)?
- spark plug wires?
- coil?

If it's been 1.5 years, it's about time for another set of spark plugs anyway. Some may say differently, but it's a good idea to do them every 2 years. And don't use crazy stuff like Bosch Platniums and Split Fires and all that crap. They don't work and actually can make your car run rough. Bosch Platniums caused my 95 to run like shite. Just used good ol' NGK.

If you replace them, use quality spark plug wires too. I've had a cheap, thin set basically melt on my car...

Have you inspected your dist. cap for scarring or cracks, etc.

Does your 98 REQUIRE high octance only?

When's the last time you adjusted your valves? It's a pretty easy DIY too.

Go through all of that first.

 

To my knowledge, the rotor button, wires or coil has not been replaced. Last time I replaced the plugs, I did replace with good ole NGK. I definitely agree with you on that.

My 98 does not require high octane, however, I have found that I get more mpg when using it.

I have not adjusted my valves. Is that something that anyone should try to tackle ? I am somewhat mechanically incline. I am definitely not a mechanic, however, I know my way around a car pretty well.

 

Even if you just have a Haynes manual, you can do it if you are mechanically inclined. If you think you can, it will save you some bucks.

You'll need some sockets and a wrench, a feeler gauge, a flat head screwdriver, and you'll need to go buy a new valve cover gasket from Honda.

You can pretty much go by the book on it.

The job can be easier with a friend to, so they can get the valves top dead center while you check and adjust, etc.

Good luck.

 

the same thing happened to me a while back when i was being stupid and threw a bottle of octane boaster in my gas tank. i think it could be the high octane of the gas because the engine isn't used to the stress of the bigger combustion...but then again octane boaster and premium gas are two seperate things but just something for you to think about.
also are the plugs gauged correctly?