Background:

Bone stock 92 civic VX d15z1 original motor
Idle is really rough and the motor shakes/vibrates under 1000 RPM
Car drives perfect and gets 50+ MPG all day.
I've cleaned the IVAC
If i set the idle correctly following the directions from Honda the car shudders and shakes badly. If i set the Idle to 1000, all vibration stops.

Sometimes when warm, the car will idle smoothly at 700-800 RPM when I have it set that low but most of the time it shudders pretty badly. It does respond very well to throttle and doesn't ever die, just shakes the crap out of the car


What can I do to stop this? I'm leaning towards cleaning the FITV next but wanted to see if anyone has had experience with this

 

so it doesnt shake at all during exceleration? just on low idle?

are you sure your tach is right? meaning when you set the idle high, does it actually sound high?


also hows your ac? if you have ac that is, is it any different when on

 

im not sure the tach is right but by ear, it definitely sounds too high. It accelerates like a dream and drives perfectly.

I do have AC which is working just fine, but i may slip the belt off just to check if it idles better

 

check the coolant level i had same issue low on coolant

 

the overflow tank is filled right where it needs to be. Ill try to add some directly into the radiator and see if it helps

 

I have solve all my idle issues an wanted to share with everyone. Yesterday driving home my check engine light came on randomly. I read the code and found code 41 oxygen sensor heater circuit. I dug deep through some service manuals and started troubleshooting. First I swapped in another 5 wire o2 sensor with no luck. I then broke out the multimeter and started probing as the manual suggests. All signs led to te ground at the thermostat was bad. I cut te ground at the o2 sensor and ran a new ground to the thermostat and bam, code was gone and the idle magically was cured.

So long story short. The idle issue was solved by fixing my thermostat ground