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Discussion Starter #1
My 93 Seville has a 4.9 pushrod engine. Not Northstar. In doing routine maintenance I noticed, upon opening the butterflys and looking down into the throttlebody, there are two 1/2 inch dia pipes or orfices sticking up from the bottom of the intake manifold. They are just below the butterflys and centered under each intake hole. I 've cleaned the throttle body several times over the years with the typical over the counter spray but had never leaned over with a flashlight and looked real good. By holding the gas or butterflies wide open I could see these pipes sticking up and what appeared to be crud buildup blocking them. There must be a 3/8's inch hole in each one so I'm thinking how did all that get in there? Well,I started digging out the front one and using a vaccume with a straw taped on the end to keep things clean. The more sticky stuff I pulled out, I began thinking maybe thats some type of sealant from the factory and I'm messing up here. So now I've got the front one sort of cleaned out but don't know to keep on or to reseal this pipe. I 've not been able to find out anything on the internet so I'm sort of stuck. Any ideas form anybody? I got a clean straight wire and stuck down into the cleaned out hole and it seemed to be about 2 inches deep. But I can't tell what these pipes do or where they lead to.
 

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White Diamond '03 DHS (with DTS floor shift)
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86,598 Posts
What you are looking at are the EGR tubes. They get clogged with carbon over the years. Use a coat hangar or what ever works and rod them out til all the carbon is cleaned out. The "sticky stuff" you pulled out I would guess is carbon disolved by the carb cleaner. Your on the right track. Now finish the job.
 

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Discussion Starter #3
Thanks a million. I'm going to change my serpintine belt tomorrow and also pick up some more cleaner. I hope this may improve gas mileage to. On short trips to and from work I get only 12 or 13 MPG.
 

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Super Moderator
White Diamond '03 DHS (with DTS floor shift)
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It should help with milage, though short trips are not conducive to good milage. Also check the FPR if your milage is bad. See the Tech Tips section.
 
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