Hi Everyone,
My '98 Honda Civic EX (manual 5-speed) is currently at 200,000 miles and makes a gargling/metallic rattling noise when I accelerate from low RPMs or whenever I’m climbing a hill. The noise sounds as if loose change is rattling around somewhere in the engine. I started noticing this a few years ago, when it was very slight and it only happened in second gear as I climbed a steep hill. Over time, it started happening in third and fourth gear, and now it is in all gears when climbing a hill or when accelerating quickly on level ground. I also notice a lack of power when this noise is occurring. In the past, if I let off the accelerator just a little bit, or if I greatly increased on the gas, the noise would disappear. Now, increasing on the gas makes the sound worse.
I asked my cat for advice, but she wasn’t very helpful.
Your engine is “pinging”, and if you don’t correct the problem very soon, very expensive engine damage is going to take place.
The cause could be simply a lack of maintenance (when were the spark plugs last replaced?), or it is possible that the knock sensor needs to be replaced, or it is possible that the Exhaust Gas Recirculation system (EGR) is gunked-up, or it is possible that the engine is running too hot.
You need to get the car to a competent mechanic sooner, rather than later, if you want to keep the repair as cheap as possible.
Offhand it sounds like you’re describing pinging. This can cause the ignition timing to retard which in turn can cause a loss of power.
Usual causes of pinging is low grade gasoline, EGR system faults, ignition timing too far advanced, and to a lesser degree; carbon buildup on the tops of the pistons.
This needs to be sorted out if pinging is the cause of this problem and continued and severe pinging can lead to engine damage or outright destruction.
In most cases this is caused by an EGR fault.
I agree with the replies given thus far. IIRC, that engine is Honda’s lean burn design, which if operating incorrectly, could also be the cause of the problem.
If this 18 year old, 200K Civic were mine, my first step would be to see if higher octane fuel minimizes or eliminates the pinging. If it does, it may make sense to just do that instead of investing in more expensive repairs.
