Hello Honda Community, I just got a 2000 Civic Ex Coupe from my neighbors who were kind enough to let me have it for free (More as a birthday gift for my 18th). Car ran good (only problem at the time was a small oil leak) and passed emissions no problem. Car had no problems and ran great! next thing you know rear shocks went out and i was okay with that, the car was usually sitting in the driveway for some time, only taken out time after time. No big deal i replaced the shocks myself and carried on. After some time i noticed the car would fluctuate around 1.2-2k RPMS. i was worried but everything seemed fine. One day on the way to my grandmas house my car overheats when at a stop light from normal freeway driving and panicked, went home waited for the engine too cool and popped that radiator cap off what what do you know, its not up to where it should be. I ended up filling it back up and closing it. Weeks go by Next thing i know i have a check engine light on 😕. A few times after the first overheat it did so many times after that and i continued to refill the radiator.A while after I scanned the engine and it came back with Code P0505, after my research i replaced the valve myself again and payed the 190$ for it. Check engine light came off and voila car ran smoother than ever and accelerated more better in my opinion. i let it sit and im soooo happy that i fixed that code, i decide to go out for a drink at sonic with my friends and when i park turn it off eat and drink and then turn it back on BOOM check engine light was on again and i was sad. i went home but noticed that when driving at around 1.2-2k RPMS it would fluctuate and jerk forwards when lightly pressing the gas (Normal driving speed in the area). i knew this feeling and had felt this problem before. i got home scanned it and what do you know Engine code P0505. i was mad because i had just spend 200$ on the new part and it still remained. After some research i found out it could be a few things. According to engine-codes.com it could be 1) Faulty Idle Air Control Valve (IACV) valve 2) IAC valve harness is open or shorted 3) IAC valve circuit poor electrical connection. I already replaced the valve and i checked for vacuum leaks (or at least i tried to). Someone told me i should try and clean the throttle body, i have yet to do so and i was going to try that in the morning (tmrw, for me its 7:55pm) Every now and then it will fluctuate and sometimes it will be okay, yes it idles high still and i can see it the computer trying to compensate for it. Any ideas/suggestions for me?



Thanks for taking the time to read this and help me out

 

welcome to the forum. just curious, where did you get your valve from to replace. the low fluctuation of idle is caused by the IACV which you changed. you might disconnect the negative terminal for a few minutes and reattach to see if the check engine light goes off and for the ecu to reset itself.

 

I replaced it myself, got it from O'Reillys. im more of a diy type of guy but i forgot to mention i did an ecu reset and everything seems to be working great, no light for 2 days now!

 

thank You for the feed back. hope the light stays off for a long time.

 

It came back on today but i noticed that it keeps fluctuating around 1.7-2.1k RPMS its really annoying. and the car like engages and disengages when i push and release the gas, jolting the car forward. Any ideas? -Sam

 

So basically here is whats happening now in no specific order:

1) Check Engine Code P0505
2) When i push on the gas softly around 1.7-2.1k RPMs it fluctuates
3) When driving while #2 is also happening, it feels like the car engages when i push the gas and disengages when i let go (Feels like a jolt Forward or back depending on acceleration or release of gas)
4) Coolant somehow always ends up into the Reservoir (No Smoke coming out of exhaust) MAYBE : Blown head gasket ??
5) Related to #4 Car overheats when it looses the coolant (Obvious)
6) When in park it idles at 1.5K RPMS this is what it looks and sounds like ( )

Things ive replaced:
1) Idle Air Control Valve (From O'Reillys) 190$
2) Coolant Reservoir
3) Radiator cap (should i replace? Maybe?)

 

Might have fixed ALL the problems, a vacuum hose was disconnected on the under side of the intake. ill keep yall updated.

 

That was the problem, a vacuum line was disconnected. but all my problems came to an end due to a driver totaling my car, rip my ek lol

 

That is good and bad news.
Sorry about driver totaling your car.