Uh, guys, we don't have variable valve timing.
The surge you usually feel is caused by the secondary intake runners opening to allow the engine to breath better at higher revs while the throttle is open wide.
The electro-mechanical actuator that does this sometimes fails and causes the butterflies not to open or only open partially.
I finally got my dealer to fix this problem (under warrantee). I gave them the following info I got off of NECO and other sites.
Intake Manifold Runner Control (secondary butterflys)
Here is something all Duratec owners should check. The IMRC control cable > runs through a small plastic guide, which is *supposed* to keep the cable > from rubbing on the upper water pump pulley. The plastic guide on our SVT > was deformed, and the cable was worn half way through the outer sheath > within 1,000 miles from delivery. > > Warren > Kurtz Kustomz Motorsports > http://www.kustomz.com > [email protected] >
A big "Thank you!" to Warren for this heads-up. Checked mine today and >found the casing half worn through after 9k miles. That plastic bridge >piece just leans over and lets the casing hit the back-side of the pulley. > >Patrick Kennedy
On 98-99 models, remove the large plastic cover (three bolts) from the front cylinder bank. Here you will see the IMRC control servo mounted to the front valve cover, and the control cable routing around the rear of the cover. At this point you will see the cable routed through the suspicious guide. Check to see it is not rubbing the upper water pump pulley. Warren Kurtz Kustomz Motorsports http://www.kustomz.com[email protected]
Date Posted: Dec/29/2000 3:10 PM
I had this same problem, so I took it to the dealer and they ran a diag on it and it indicated that my Intake Manifold Runner Control (IMRC) actuator was faulty. This thing must have been bad for awhile, talk about low range pull. This cat claws have been sharpened.
I hope this helps you. I've been hassling with this for a long time and finally got it fixed this week. The postings seemed to do the trick. Good Luck.
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