Curious: Change from 3000 to 1500RPM for IMRC?

[jer1303]

While troubleshooting my non-functioning IMRC's; I noticed that Ford changed the spec from opening the valves @ 3,000 RPM to 1,500 in '98. After figuring out my front (left?) acutator is leaking, I taped the line shut. Now the rear acuator on my '98 works as it should, and opens the secondary intake tubes at 1,500. So I have a couple questions at this point.

Does anyone know why Ford changed this value? Was there an intake manifold change from '97 to '98? I don't think this van spends that much time below 1,500; it just seems like a small amount of range to impliment a system like this. (My old SHOs opened them up at 3,950; but I understand that's a totally different application!).
I was considering wiring the broken one shut for the time being, but if it opens that early...maybe not.

Second, I've read that the Dorman acuators avilable at RockAuto don't work right eletronically. Has anyone had sucess with these, or am I stuck getting the $150+ Ford unit? Any advice appreciated.

TIA,

Jeremy

[wiswind]

From what other's have posted.....I would get the FORD ones......try www.y2kford.com which is millennium ford in seatle.
I just don't like installing stuff that does not work right....or hold up.....
It is interesting that they lowered the OPEN rpms.....guess that they wanted to give the extra power boost at a lower RPM.