Coasting or sitting at a stop sign the idle will sometimes increase and the car will lurch forward.

Happens in N too. Idle just increases to about 1800. Just for a couple secs then back to normal, 900-ish. A/C on or off.

Any ideas?

 

bet a dollar your idle air control hose is broken
#30637166 $10.43

 

what year car is that drawing from? My hose is on top and to the left, closer to the intake. there is a much larger hose underneath, but it goes to the inner cooler.

Thanks for the reply, but I am sorry to say, it is not broken. I removed it, capped an end and blew thru it, or tried to. Plus I sprayed starter fluid all around that area with the car running. there are 5 or 6 small hoses there. No rpm change.

a search on another forum resulted in 7 or 8 posts of this same problem, but no one replied. I did see one suggestion talking about a fuel pressure regulator.

 

I started poking around the FP reg. Pulled the spring clip and it popped out.

There is a screen inside that is shaped like a donut. If you can imagine, this donut is cut into 2 pieces, or at least partially cut. 2 "C's" that are barely holding themselves together.

2ndly the vacuum hose is 2 "C's" with a poly-tube connecting them. I do have cracks in one "C" and a nice hole in the other.

So, do I have to buy the whole reg, or is the screen available? Hoses are needed too. I found the whole reg for $207 and it comes with hoses. I might be heading to pull a part.

you should be able to see this album on Flickr.com Click the link below.

https://flic.kr/s/aHskGqXapU

 

The screen is broken. I highly doubt you can find just the screen but who knows. Given the hose is also broken I'd break down and but a new regulator as they are known to be a weak point in the older S40. The price is $207 now eh? Good grief, they are getting up there.