Accord shakes on approaching 100km/hrs
 

Good day to you all, my 1998 accord shakes occasionally on approaching 100km/hrs on the highway, i am thinking probably some of the spark plugs are bad or is it the fuel filter? Please kindly respond. Honda accord 98, auto transmission, Lx, 2.3L, 4cylinders. Thanks

I rather doubt it is either the spark plugs or the fuel filter. I'd be much more inclined to think you have an issue with either tire balance or an axle going bad.

others are suggesting possible failure of the fuel pump because the vehicle tends to sputter at high speed say 90 to 100km per hr. I did the wheel balance and alignments just a month ago. please reply thanks

Your problem is likely NOT a fuel pump failure. You can test fuel pressure, but DO NOT replace the pump.

Do you have a scan tool? Have you checked for any engine codes?

Thanks, i will do the scanning this week and check for engine codes, but i don't know if i can travel with it for a journey of 68km tomorrow and come back the next, although the two back tyres are bad, i am also considering looking at the Injector nozzles if it is blocked. please how good is Injector cleaner? I have not use one before, my initial fear is whether it will not cause any new problems. Hoping to hear from you.

Injector cleaner: I've never seen it do much of anything

Shaking: if it shakes on the highway at 60mph it's usually the tires. Do you have crappy, cheap tires on it?

Also, when it's shaking on the highway at high speed, put it in nuetral and take your foot off the gas and see the shaking continues

Sputtering at highway speeds usually points to a fuel pressure problem. You can test the pressure with a gauge, maybe you can rent one from an auto parts store. Most cars have a port to hook it up to. There's a spec for the fuel pressure in the book.
I think most accords have a scheduled maint interval for the fuel filter. If that hasn't been done, that would be a good place to start.
Usually I would think a fuel pressure starvation prob would set a lean code, but maybe you haven't reached the threshold yet.
Good luck, and please post your fix when you get it figured out

I used to have a 1998 and it did not have a fuel filter up in the engine compartment. Only had a screen at the pump inlet, inside the fuel tank. But that might not be true for a car that's built for Nigeria.

Mine looked like there were connections for a filter mounted on the firewall. But all that was there was a tube connection, no filter. Rilex, look on the firewall for a fuel filter, & think about changing that unless you know it's fairly new.

Otherwise, I'm inclined to think about tire balance issues like the others. Get going to the speed where it's shaking, then put the transmission in neutral & coast. If it continues shaking, then it's absolutely not the fuel supply system (injectors, filter, pump, etc).

Thank you all for responding. The shaking has reduce since i did the following; apply grease to the shaft at the right hand side, change two of the four spark plugs, change the upper and the lower ball joints of the same side. The next thing to do is to inspect the fuel filter for dirts and particles. Now going to the speed where it is shaking, if i place the transmission in neutral will it not cause some damages to the transmission system at that speed. i know we are trying to assess if the fuel supply system is causing the shaking. THANKS.

It's OK to shift to neutral & coast, with a couple cautions. I wouldn't do this every day all the time, but it's OK just for figuring this out.

Lift your foot from the accelerator pedal as you shift the gearshift to Neutral, so the engine doesn't rev wildly. I think if you don't press the button with your thumb, that will prevent you from pushing the lever into Reverse (which would be BAD). DON'T switch off the engine - leave it running.

Shift back into Drive, or if traffic allows it's slightly better to slow down towards 50 km/hr then shift back into Drive.