My engine has recently began to 'rev' with a rough idle while in the park position. The RPM gauge fluctuates up and down, and you can hear the engine rev accordingly. I've uploaded a video (ignore the crackling of the paper bag in the background) that displays this issue.

Any ideas on what could be the cause?

Here's a synopsis of recent repairs/maintenance:

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I have been having a few problems with the distributor/cap and plugs. My car would initially jolt heavily and then shut off while driving, or sometimes fail to start completely. Haven't had this issue since replacing the distributor cap, though.

http://www.youtube.com/watch?v=hUgbHuVYnW4

Any and all help is greatly appreciated.

 

Could be an air bubble in the coolant system, since your radiator replacement. Make srue your coolant has been bled properly.

Other than that a surging idle could also be caused by a vacuum leak, or an issue with one of the idle air control valves. AKA the (IAC) Intake Air Control and (FIT) Fast Idle Thermal valves.

 

GhostAccord, thanks for the reply.

Here's the video: http://www.youtube.com/watch?v=hUgbHuVYnW4

If my coolant system hasn't been bled properly, how would I remedy that? Remove the radiator cover and run the engine for 10-15 minutes until the air bubbles are gone?

...eHow probably has info on this...

 

That works, or you could use the bleed screw on the thermostat housing. I usually opt for parking the car facing up a slight hill and using the radiator cap method as you mentioned.

 

^ Your check is in the mail. I'm going to give this a try right now. I'll let you know how it turns out.

 

If only.... lol

Good luck!

You could also try resetting your engine control unit (ECU). Do this buy disconnecting the (-) battery terminal for 30 seconds. Or pulling the "back-up" fuse (7.5amp) Make sure if you have a factory stereo that you have the reset code before disconnecting the battery or pulling the backup fuse.

 

Good deal. I'll definitely explore those options as well if this 'bleeding' doesn't work out. I'm actually in my car now bleeding the radiator - the rough idle and revving are both not present, so that's a good sign.

I'm hoping one issue with this car can be solved as simply as this. Wonder if I can be so lucky...

 

GhostAccord, you're alright by me. After 15 minutes and a quick go around the neighborhood, the issue has been resolved. Many thanks for your help.

 

GhostAccord - My 1993 Civic Si HB - has been sitting for some time. I decided recently to get it back on the streets and in fighting form. I noticed that I too have the revving idle issue. It revs up and down at idle. I have replaced battery checked all fluids (including coolant) and bled coolant to ensure no air bubbles. If the problem then lies with the (IAC) or (FIT) - is there anyway to possibly clean them or do something to test it without buying a new one (to ensure thats the problem before buying a new one)? Also after a few light test drives up and down the road i get the check engine light after a few minutes (possibly when engine gets up to temp?). Any ideas?

 

Hit the IAC while the engine is rough idling. If it changes then that's the problem either replace it or get it off clean and test it.

Get to the FIT and take the cover off. Rotate the plastic block ring clockwise. Do not overtighten.

Check and clean your MAP sensor too.

 

Try what @aznrida said if bleeding the cooling system doesn't work for you. Give it a week at least even after you've bled the system. It only happens in neutral or park correct?

 

Thanks for the help GhostAccord and aznrida and everyone else. It only does it when its idling either in neutral or with the clutch pedal depressed. I wasnt able to get to this weekend will try again next. I would really like to do one method at a time to see what was actually causing it I will be making a video of each step to publish with - what actually cured the problem eventhough i may still clean and refresh all sensors etc cause it probably needs it. I just really hope it isnt a vacuum leak cause i imagine they are hard to find but on the other hand easy to fix.

Until next time,

 

i had a similiar problem in my 90 accord. seems i had a intake gasket fail...

 

Hey guys, I have the same issue with my 2002 Acura 3.2 CL. It has been sitting idle for 2 years and I decided to start using it again.

What should I look into to fix this problem?

 

Hello, I am very interested in learning what caused your engine to rev while in park. My father had similar issues today with his 2015 Honda CRV Touring. He was in drive at a red light when it started and he put the car in neutral and in drive while he was pushing on the brake only. We are very concerned and he doesn't feel safe driving the car. If you could share any insights it would be greatly appreciated. Thank you in advance.

Kristin