Driving a 98 accord lx. 4 cyl, manual trans. There is a rough idle unless i'm on the gas. When I go to accelerate the car jumps pretty bad. I have been told it is the idle air control valve however, I have read many posts on other sites that say that is generally not the problem. Any help with some trouble shooting?

Thanks

 

Could very well be the IACV if it only rough idles when your off the gas. The IACV is supposed to allow enough air in when the throttle is completely closed. Not enough air = running rich = rough idle.

The only other thing I can think of is getting a new PCV valve ($3) and cleaning out the EGR ports.

 

I had a similar stumbling issue with my '93 and cleaning out the EGR ports made a big difference. It completely fixed the problem.

 

pardon my ignorance, but what are the egr ports?

if that doesn't work for me, what do i have to remove to replace the iac?

 

Use the search feature. Better yet, look in the DIY section.

 

Not enough air at idle = low idle speed, not rich, the ECU will adjust idle mixture. A low idle speed may cause vibration due to idle speed itself but not mixture.