EGR valve trying to find out if a 1999 honda civic SI has an EGR valve. If there is one, where is it and how do yo ureplace it?

then you need an egr valve

I'm guessing near the exhaust manifold.

EGR is exhaust recirculation valve, is attached to your exhaust pipe right after the exhaust manifold, you can simply remove it using the correct socket wrench or combination wrench to remove the bolt that fastened the egr.

You are probably going to need a syncro on third gear, trans has to come out and be taken apart.

Yo pregunto por el consumo de aceite de 750 cm. cada 800 Km si es normal

yo tengo un civic 2005 y el numero esta en una tarjeta junto al manual del carro pero hace poco tiempo descubri que tanbien esta en un sticker al lado del gabetin brontal, debes abrirlo y buscar al lado por fuera, mi carro lo tiene espero que el tuyo tambien, suerte

You need to compress and turn the piston at the same time for it to work.

Pull vacuum on egr valve with engine idling and see if engine stumbles and tries to die until vacuum is released. If this DOES NOT happen the egr exhaust passage is plugged will need to remove egr valve assembly and remove carbon from passage into cylinder head.

if the check engine light is on it probably the egr valve but if the light is not on the idle control solinoid is dirty or broken

try the control for the egr valve and check the egr valve if open
car will not idle from a 85 civic owner that did just a egr replacement and it was fixed ( ebay new egr valve was only 22.00)
parts store 69.00