Today I changed the air cleaner filter(was very dirty) and cleaned the throttle body (On-car). After this, the car started idling at 1500rpm. The normal idle is around 700rpm. I disconnected the IACV and tried to set the base idle at around 650rpm. After screwing the idle screw all the way in, the idle remained at around 850rpm. I went thru the procedure of stabilising the speed at 1000rpm and slowly releasing the gas pedal.

The thing is that after reconnecting the IACV and clearing the ECU, allowing it to idle for about a min without touching the gas pedal, the idle speed is around 720rpm (within specifications!) problem is the idle is rougher than normal and there is a noticeable lack of power. Throttle cable is properly adjusted with appropriate slack, if the FITV was leaking the problem would have been there before and the idle would continue to be high with the IACV connected. Same goes for vacuum leaks. Am I missing something here?

 

Did you clear the ECU by pulling the 7.5 amp radio fuse in the engine bay box for a minute?

Since you took of the throttle body, you had to add some coolant. Did you bleed all of the air out of the system via the valve on top of the thermostat housing?
If I remember correctly deserthonda always mentions that you should take out that idle screw and clean that passage.

A leaking FITV should raise your idle and ususally it fluctuates. You can try covering up the FITV port inside of the throttle body with your finger when the engine is warm. There should almost zero vacuum on that hole. Covering both the FITV and IAC holes should cause the engine to stall. If not, then you have some sort of air leak. Did you replace the TB gasket? Did you clean the IAC valve with throttle body cleaner?

 

Yes, the ECU was cleared by pulling the 7.5 amp fuse. I did not remove the throttle body...cleaning was done by removing the air hose and spraying Amsoil Power Foam directlyinto the TB while engine idled. I know about cleaning the idle screw but that's usually done if idle is too low?....i'll give it a try anyway. I'll also try your method of testing the FITV.

I'm also thinking that maybe the ECU is adjusting the timin....making it impossible to set base idle? I have searched diligently under the glove compartment and cannot find a Service check connector to jump.

 

Maybe some dirt dislodged & worked into the passageways for that idle adjuster screw.

Right RPM but rough running? What about plug wires, cap & rotor? Did you clean them (with what)?

 

The plug wires and distributor paraphrenalia are ok...in fact I changed the dist o-ring a couples weeks ago and took the opportunity to clean up the contacts and rotor. Car was operating fine after. The only reason why I decided to clean the TB is because I was changing the air filter and had the time.

What is really puzzling is the impossibility of setting the base idle while ECU controlled idle is rock solid at 720rpm ( under all load conditions). Later I'm going to clean the idle screw and test the FITV...perhaps there is a small leak

 

By the way, if dirt had gotten into the idle screw passageway, wouldn't that result in low idle? Logically, it would seem that there is some small air leak somewhere

 

I had the same problem. The car is missing erratically. Just keep driving the car until all the crap has worked through; it might take a few days. You may want to throw a new set of plugs in once it starts running better. Next time do yourself a favor and remove the TB to clean it, I know I will.

 

Boy! those are my sentiments exactly. I'm still kicking myself for not taking the necessary time to do the thingproperly. Shortcuts never work...just lead to more work actually. Anyway, the FITV has a slow leak....it is till sucking air after the car has fully warmed up. I'm waiting for the engine to cool down so I can work on it

 

I'd wait a week and Seafoam it .... it may make it worse at first, but at least it will help the crap work its way out.

 

as for the service connector for the diagnostic tool hookup try looking under the steering wheel or anywhere in that general area under the steering column or dash, all the ones I check for ppl at work are under there.