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Auto_Enlightenment, Team Leader Tech
Category: Honda
Satisfied Customers: 237
Experience:  Honda Master Technician & ASE Master Technician
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1998 Honda civic ex: neutral or after heavy acceleration..rpm..drops

Customer Question

hello my name is XXXXX XXXXX have a 1998 Honda civic ex, standard. For some reason my car keeps stalling usually after I shift it from a drive gear into neutral or after heavy acceleration the rpm just drops all the way sometimes it will drop all the way and go back to about 500rpm. can you help me? when its just idling after cold start it idles about 1000 to 1500 then stay at 1000 then drops to 500rpm.
Submitted: 4 years ago.
Category: Honda
Expert:  Auto_Enlightenment replied 4 years ago.

Auto_Enlightenment :

Hello there, I am a Master Automobile Technician certified by Honda and ASE. I can help you with the problem you are having with your Honda!

You could have a malfunctioning Idle Air Control Valve or Vacuum Leak. I would do a quick check for vacuum leaks by spraying silicone spray around the intake manifold. If there is a leak it will suck up the silicone and change your idle. If it does then you have a vacuum leak.

You can also try turning out the idle speed adjustment screw on the throttle body to raise the base idle up some,

When it starts cold and idles 1500rpm, that is normal. This is your fast idle valve which raises the idle while cold to help heat the motor up quickly. Once its hot the Fast Idle Valve steps out and quits bypassing the extra air which lowers your rpm.

Idle spec when hot should be 600-800 rpm

Auto_Enlightenment :

The fact that it stalls, makes me think you have either a vacuum leak or even possibly an egr valve which is hanging open.

Auto_Enlightenment :

Hey, just wanted to check in to see how it was going. Let me know what I can do to assist because I am here to help until we get this figured out. Fixing this for you is my goal.

Your Positive Feedback is greatly appreciated and helps improve my reputation and standing as an Expert on JustAnswer.