btracy

Thanks for the reply. The EGR valve seems to be fine. Something is causing the vacuum to cycle under load. I checked the electric valve with direct voltage and it opened and closed as it should. I am going to replace the EGR position switch and the vacuum modulator. They were both slightly out of spec. when I tested them. The car has yet to throw a code, it continues to surge when you are diving at a constant speed. Thanks again for the responses.

Thanks for the reply. I tested the vale itself by putting vacuum to it. It seems to work properly, it acts like the problem is whatever controls the vacuum. I am not against replacing the valve I just want to make sure that is the problem. Thanks again for your response.

Hello All, I have 97 ES300 that surges under a load.(driving or stationary w/ brake on @ 1500+ rpm) There are no codes. If I disconnect the vacuum line directly @ the EGR it will stop. If I unplug the position sensor it will stop(on top of egr). If I unplug the small valve(elect.plug or vac lines) that feeds the vacuum to the EGR it stops. I cant seem to narrow down what the exact cause is. Any help will be greatly appreciated. Thanks