High RPM Start

[Roadking]

'97 4.0L SOHC
When I start the engine it revs up to about 2000/2500 rpm for about one second, then settles back to about 900/1000 to idle.
Is this normal?
It also seems to make a hissing noise when it idles.
Any ideas? tips? or where to look?
Thanks!

 

[skiplorer]

I also have a '97 4.0 SOHC, and mine does the exact same thing as yours. The high idle at first, then dropping low. And the hissing, almost like a belt noise at idle. I think the hissing is the SOHC intake, i think its almost like a supercharger concept, kinda like a blower. I'm hoping these things are normal? Please let me know if you find out otherwise. thanks!

 

[Ray Lobato]

Roadking, skiplorer,
I got this answer from another Explorer web site.
check it out.
http://forums.vmag.com/suvexplorer0199/messages/1067.html

FYI My 97XLT does the same thing. It is a SOHC also. Dead Link Removed

------------------
Happy Wheelin'
Ray L.
97 XLT 4X4 4.0L SOHC

 

[Ray Lobato]

I got this from a Ford Tech on the web.

ubject:
Re: allexperts.com question
Date:
Wed, 26 May 1999 06:17:17 EDT
From:
JWFORD55@aol.com
To:
rlob@tomatoweb.com


Hi Ray the idle raising up at startup is just like a fast idle on a
carb use to do,but I will check on something about it going to 2500 RPM.
That may seem hi, but I think it is normal. The other noise you hear at idle
is normal, it is the air going through the plastic upper intake manifold, and
you are right, it is only a concern with the 4.0L SOHC engines. Everyone
asks about that when they come in for their first service. So, for the most
part, as long as it keeps doing that, the truck is ok. We had similar
questions when Ford went to using light aluminum intakes, noises with them
too. I hope this helped you some, but you are not the only ones commenting
on that noise. Let me know if I can help with anything else.
Jim

------------------
Happy Wheelin'
Ray L.
97 XLT 4X4 4.0L SOHC