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2001 Honda Civic LX - Idle Speed/Stalling Issue

My wife and I are the original owners of a 2001 Honda Civic LX with a 5 speed manual transmission, 127K miles, synthetic oil, and strictly Honda dealer maintained that’s been (is) a GREAT car. Here’s the problem - when the motor is warm after driving, the car will sometimes die when putting it in neutral coasting up to a stop light. I watch the RPMs and they’re at about 400 or 450. Today, we came off the highway, I was coasting in neutral the last few feet, and I tried to put it in 2nd gear to merge into the next lane, only to find out it the motor had died, and a car was barreling down at us. Yikes! I’m thinking the problem lies with the idle…perhaps a sensor or adjustment is necessary? Does anyone have any ideas?

The computer controls idle speed via the Idle Air Control (IAC) valve. If the valve is dirty or worn you can have incorrect idle speed. A problem in the IAC control circuit can also cause this problem. Normal idle speed should be ~750 rpm.

Your Honda dealer can easily fix this for you, or you can take it to an independent. Either way it shouldn’t cost too much.

If the car is still moving when the engine stalls you can put it in gear and take your foot off the clutch. The engine will restart, assuming the ignition is still on.

I sometimes get the same symptom with my 98 Civic DX because the idle speed is too low to handle the air conditioning compressor. I don’t mind this symptom in the winter since it saves fuel. When it happens (usually about once a year), spray a little carburetor cleaner in the throttle (according to the directions on the can) and it clears right up. If you want to be more thorough, have your mechanic manually clean the throttle and check the items listed above by mcparadise.

Honda calls their part, which controls the amount of idle bypass air, Electronic Air Control Valve (EACV); (or, they did on previous models). The Valve could be dirty and not passing enough air. Also, the throttle body may be dirty. Clean the air passages to the throttle body bore and throttle plate, and the EACV with Throttle Body Spray Cleaner. Make sure the air filter is clean. If it’s dirty, it can reduce air flow and adversely affect idle.
If the spark plugs and wires, distributor cap and rotor, and fuel filter are original, they could causing the problem.

Thanks everyone for their help. What I neglected to add was that I am stationed in Germany. I took it in to the shop today, and they diagnosed it as an “electrical load detector high voltage,” with an error code of P1298. Honda advised it is a common repair. Thanks for the information!

“Honda said…”? Do you mean, “the Honda repair shop, or, Honda Europe”?
I hope that the repair shop has some idea of what it is that is causing high voltage (and where), or, know HOW to diagnose it. Killing the “messenger” (replacing the electrical load detector) isn’t a cure. It’s just doing its job.

Thanks for your quick reply, Hellokit. We actually took it to the Bosch shop and they ran their diagnostic tests with their equipment and came to the conclusion it was the high voltage load. They actually ran it to the German Honda dealer the next block over (who regularly performs the service on the car) just so they could double-check. Honda confirmed it and Bosch said it is a 54 Euro (approx $80) sensor that’s been ordered. I wish I could tell you more, Hellokit, but my high school German is rusty and this is what I was able to decipher from the paperwork and conversation. What do you think? Is this on the right track?