Regardless of load, speed or rpm, my 1995 accord EX 2.2 VTEC Automatic runs rough (stuttering, sputtering) at cracked throttle (approx 1%-5% open). At 5%-100% car runs fine.

At first I though it was EGR valve. EGR is good.

Car has 200,000 mi. All stock.

There's no check engine light. I realize that that the check engine light bulb may possibly be blown but what are the chances of that? Slim to none.

Can someone help me out here?

I checked all the vacuum hoses by the intake manifold.
I separated the intake duct from manifold and sprayed throttle body liberally with throttle cleaner and ran it through - to no avail.
Could it be the IAC? Not likely - car idles fine.
Could it be the Fuel Filter? Not likely - Car runs good at above 5% open throttle.

These symptoms came on after I ran a tankfull of gas with injector cleaner at high rpm's 4000 to 5000 rpms.

This might help....
http://www.topendmotorsports.com/jp/...uumdiagram.jpg


Thanks,

 

If the check engine light turns on for two seconds when you initially turn the key to the II position, then the bulb is fine. If the light does not come on, then replace the bulb.

Have you done all the maintenance, like the spark plugs, distributor cap, and distributor rotor?

Make sure that you cleaned both sides of the throttle plate and the bore by using the throttle body cleaner and an old toothbrush.

 

Does the idle speed correctly adjust for auxilliary loads (AC, lights, window winder motors etc etc)?

I know that disconnecting the IACV (electrically) causes a symptomsimilar to your description (harsh on / off throttle behaviour, associated with injector overun cut off I think). However, disconnecting the IACV does throw a CEL, which I assume must also be the case if the IACV is electrically malfunctioning.

If the IACV is blocked (or otherwise not passing air for some reason), but is OK electrically, then it won't cause the same harsh on / off throttle behaviour.

 

dfly9891:

I have the same problem with my '95. Did you solve the mystery?

Rob

 

Rlc138-might start your own thread, don't get me wrong - THANK YOU for searching first. Give the full details of you issue and what has been done to date to resolve. Also anything (work done to car, other issues, ect) leading up to the issue.