btracy Posted August 31, 2008 Share Posted August 31, 2008 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 Quote Link to comment Share on other sites More sharing options...
brucelee Posted September 1, 2008 Share Posted September 1, 2008 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 I just replaced my EGR valve due to the same symptoms you describe. Drives like a new car. Get it replaced. You will not be sorry. PS-I have a 97 also. Quote Link to comment Share on other sites More sharing options...
btracy Posted September 1, 2008 Author Share Posted September 1, 2008 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. Quote Link to comment Share on other sites More sharing options...
spalkin Posted September 4, 2008 Share Posted September 4, 2008 Excellent job btracy! Don't spend a dime until you know. Check the EGR valve for clogging. It might operate but if it's clogged, it doesn't matter. Check the vacuum switch under the cover. It can be suspect sometimes. The system is very simple. And every part of it can be tested very easily. Do you have a check engine light? When you check the EGR valve, apply vacuum to it and watch it. It should hold and not move. Quote Link to comment Share on other sites More sharing options...
btracy Posted September 4, 2008 Author Share Posted September 4, 2008 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. Excellent job btracy! Don't spend a dime until you know. Check the EGR valve for clogging. It might operate but if it's clogged, it doesn't matter.Check the vacuum switch under the cover. It can be suspect sometimes. The system is very simple. And every part of it can be tested very easily. Do you have a check engine light? When you check the EGR valve, apply vacuum to it and watch it. It should hold and not move. Quote Link to comment Share on other sites More sharing options...
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