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I have a 2001 v6 accord with 170,000 miles. It started to idle very rough and even died if i didn't keep the rpm up. The headlights also brightened up when i pushed the gas. I replaced the alternator and it seemed to fix the problem. After a couple days it started back with the same symptoms. I am not sure where to look next?

Texastophat

Try checking the tension on the belt that connects the alternator to the crank, and I would also check your spark plug wires. If they're stock I would go ahead and replace them.

michaelrush01

Use a voltmeter to check battery voltage with the key off, it should be 12 volts or more. Next, start the engine and check battery voltage again, you should see 13 - 14.5 volts if your charging system is working properly. If key off battery voltage is below 12v, your battery needs to be properly charged before it can even be tested properly. If you don't see 13v+ with the engine running, your 'new' alternator may be defective or the belt could indeed be too loose.

If you don't have a voltmeter, go to Advance Auto or Autozone, they will check your battery and charging system for free.

It's also possible that your battery is marginal and charging system is fine and something else is causing your engine to idle too low and die. That would explain why your headlights dim.

There are several things that can cause low idle so don't just start throwing parts at it. Taking a methodical approach to diagnosis will find the real problem and save you money in the process.

Good Luck!
Michael Rush

accordturb96

to add to everyones suggestion, make sure your connections are nice and tight