Dads 95 4cyl. Accord just began this erratic idling issue yesterday, occurs when either parked or running. Car will not stall but feels as if it wants to, both when running or at a stand still. Eventually Revs back to normal. I have read it can be a few things so where should I begin troubleshooting. Car has 200,000 miles..Any/all help or suggestions are appreciated ..Thx in advance

 

First, bring all the normal tune-up stuff (spark plug, etc.) up to date. Erratic idle can be caused by that stuff.

Then check the cooling system to remove any air bubbles. There should be a bleeder screw back at the thermostat housing.

Clean throttle body. Clean IAC valve (back of intake manifold). Clean FIT valve (under throttle body). Any vacuum leaks?

Could be a few other things, like PCV or EGR valves. Eliminate the easy stuff first.

 

Thanks Jim..
Plugs changed about a yr ago along with wires, ran concentrated fuel inject cleaner in about an 8th of a tank and ran car to almost empty then filled up afterwards. PVC looks, sounds and good airflow. Need to look into the IAC valve u mention as welll as FIT valve. Checked for clogged Cat Converter by feeling for easy, strong flow out of exaust, which was good. At this point I am thinking vacuume leak somewhere but can't pinpoint. Drove it a little more today and noticed it just struggles (putts along) when acelerated then eventually picks up.
Will also need to check the cooling system to remove any air bubbles.

 

Don't forget to clean crud out from bore of throttle body. Search in DIY for something about dismantling the FITV & tightening it.

If you're an old Honda guy, the rest of this stuff will be old news for you, but...

Throttle cable MUST NOT hold the throttle open even a little; it should go slack.
Mechanical throttle stop screw must only just stop it from wedging stuck closed.
(Either of these can be messed up by a misguided former owner...)

Then look for the idle-adjust screw, recessed in a hole above the throttle body bore. Adjust the so-called BASE idle like this:
Engine warmed up completely.
All electrical loads turned off.
Jumper the SCS connector with a paperclip (like you're reading error codes).
Unplug the electrical plug from the IAC valve; this should almost stall the engine.
Adjust idle screw for about 550 rpm. (Yes, that is NOT the normal operating idle.)
Turn it off; plug in the IACV; let it cool down.
Reset the ECU (remove back-up fuse or pull a battery cable).

Now start the engine without touching the gas pedal at all.
Let it warm up without touching the gas pedal.
Done.