How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site. Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask tklusman3 Your Own Question
tklusman3, ASE Certified Technician
Category: Honda
Satisfied Customers: 122
Experience:  Owner independant import repair shop. 35 years experience
Type Your Honda Question Here...
tklusman3 is online now
A new question is answered every 9 seconds

I have a1996 honda civic that after warm up idles up down up

Customer Question

I have a1996 honda civic that after warm up idles up down up down up down. like your revving the gas. anyone have any ideas?No CEL codes stored or pending.When I slowly unplug the MAP sensor and plug it back in it will calm down.(until you shut down and restart it.Then same thing happens again.Replaced MAP ,no change.Thank you
Submitted: 8 years ago.
Category: Honda
Expert:  tklusman3 replied 8 years ago.

I have seen this a number of times and sometimes you have to reset the idle stratagy. Make sure you have the radio code. Remove the 7.5a BACKUP fuse from the under hood fuse box for at least 10 seconds. Make sure you do not have a scanner hooked up. Replace fuse. start engine and let idle for at least 5 min with all electrical loads off. after the radiator fan runs let idle for anouther 5 min. if after this time the idle seems too low there is a air bypass screw located at the throttle intake. sometime it has a rubber plug and sometime it has a yellow paint on it. turn this out to increase idle.


Hope This Helps

Customer: replied 8 years ago.
FYI.After trying the map and no change I put the old one back in and returned new one.Your answer still remain the same? Also,the vehicle is 20 miles away so will take me a while to try this and accept answer.THANK-You and will give it a try asap.Larry
Expert:  tklusman3 replied 8 years ago.
Yes, this is the Idle relearn procedure. sometimes this get out of whack. also if you do have a scanner you should go through a clear codes routine first, then the idle relearn.
Customer: replied 8 years ago.
Followed your procedure to a "T". Replaced fuse (after 15 sec) and refired. Immediately went into its reving fit. Continued with your instructions.Shut down at end and refired to same fit.
Expert:  tklusman3 replied 8 years ago.

Sorry I have been away from the computer a couple of days

You may need a little cleaning , But first, check and make sure it is full of coolant and oil. If you engine is not full of coolant and the intake does not warm up correctly not only does this mess with the coolant sensor but it also contributes to the build up of coking in the intake and idle air control. There is a small metal hose that runs between the back of the head to the intake manifold. It should get hot. If it does not then your either low on coolant or there maybe a coolant passage stopped up. this does happen. also air in the system is a problem, this hose is somtime a good place get it out. These Hondas as well as many of the feul inj ones, had a problem with cokeing of the throttle plate. idle passages and intake manifold,as well as the EGR. sometime the intake would have to be removed to do this. You may be able to clean the throttle body plates,and idle passages. You may be able to gently spray a good intake cleaner (not a carb cleaner) into the throttle and idle passages while idleling to help break loose the residue that gathers on most all these parts. do this for a short period of time(1 Minute or less) , Then shut it down and clean the throttle with a small brush.(toothbrush works well). start back up and try to clean out with the cleaner for a short time again. Trying not to kill the engine spray into the idle air pass. After this you may need to do anouther idle relearn.


If this does not help any you may need to remove the intake or the idle air control to clean further or possibly even replace the idle air control if this does not free it up.


sorry for the delay


Hope this helps

Customer: replied 8 years ago.
I've "power foamed" the throttle body and sprayed while running.(after toothbrushing)where is the idle air control you spoke of?
Expert:  tklusman3 replied 8 years ago.
mounted on the back side of the intake manifold close to the throttle body. Did you check your coolant level and that pipe? Does your intake get warm up by the throttle plates?
Customer: replied 8 years ago.
spent the day pulling/cleaning throttle body/intake.YES coolant level,oil and pipe gets hot.After cleaning did the re-arm and NO Luck.Still idles perfect til it warms up then goes into fit...I'm lost,You too?