Hi Everyone,

My dad's car is having some problems..

It's a 98 Civic DX with an automatic d16y7

The idle fluctuates in park/neutral..

i would say 600 to 1500.. rpms

I have tried cleaning the IACV and that didn't work, so I replaced it with a new IACV.. Still same thing..

I've also checked for vacuum leaks, checked for any kind of misfire..

Could anyone here be of any assistance?

Thanks in advance.

 

Any CEL codes? If not, try bleeding the cooling system:

Bleeding may take 20-30 minutes.

1) Park the car on an inclined driveway with the front end higher than the rear.

2) Push the dash heater lever/**** to MAX heat.

3) Follow the directions in the diagram below

 

I'll check it out when my dad comes home from work!

Thanks man.

Hopefully this works.

 

Only in park @ idle? What happens when you/he drive it around? Did you try having the injection system cleaned either professionaly or tuneup in a can?

 

The throttle body gunked up maybe?

 

Bleed your cooling system first. Sometimes a faulty oxygen sensor gives idles problems. Any CODE?

 

Bled the cooling system, no go.

 

1) Double check for vacuum (EVAP, PCV, booster, FPR, cruise, etc.) or intake air leaks (TB and IM gaskets).

2) Test the resistance of the 2-wire ECT sensor under the distributor.

3) Test whether the TPS output voltage is correct at closed and wide open throttle and changes smoothly through the range.

4) Try adjusting the idle screw on the throttle body.

 

It was the intake manifold gasket!

Thanks.