Rough Idle

[aquanetkill]

I think you may have solved my problem as well. I have the EXACT same problem with my 2002 focus. I will go to autozone tomorrow to see if i get the same code as you but i did just hear a hiss just like you described tonite. How hard was this hose to replace? What tools and how long did it take you? Instructions somewhere. I am not too car savy but i have a technical mind and can normally figure stuff out with a little help. please let me know as this problem is really starting to aggrivate me! Also what is the technical name for the hose?

[killer ZETEC]

hmm. is that why my idle is at around 700 or so?. it's kinda cool but the car seems like it'll die out. mine is an 03 with the zetec. maybe i should replace this seeing as though i have around 50 k on it (i did the tune up myself and didn't forget anything. it was cheaper this way anyhow).

[ChaosWarlord26]

I actually had 2 bad hoses. Has anyone heard of crank case ventalation? Well this was the real bad hose. It goes the crank case on the top of the motor to the back of the intake mani. It has a hard plastic core with rubber elbows one on each end. One of my rubber elbows was in real bad shape So I replace it with High temp Silicone tubing. and has been runing great ever since. Hope this helps out a lot of people.

[ChaosWarlord26]

I have just taken photos for those who want to see......
First Pic dirty motor and CAI



Next is a side view



Next is the crank case vaccuum hose.



Finallay is the part of the hose that I replaced from the Vaccuum hose to the Intake



I hope this helps everyone with the problem I had with future problems that everyone else may have.

[aquanetkill]

this fixed my problem in less than 5 minutes! my guess is that this hose has been bad for a long time and just recently turned my check engine light on. my car idles like its brand new now and hasn't done that in a long time. So if your looking for the cause of a rough idle check the elbow of this hose even if your check engine light isn't on.

[afro_ken]

Aloha!! This post is fantastic!!! My check engine light came on! I tested with a OBD2 which gave me a code of p0171= too lean (bank 1). I didn't know where to begin. O2 sensor, fuel filter, etc... BUT no the hose in this post was the culprit to my problem. thanks!!!

[bluefront]

Nice to find an older post where the problem was solved and explained thoroughly.

First off.....I don't think a rough idle is "normal" on any stock Focus. Of course when you modify the engine in any way, all bets are off.

Finding most vacuum leaks is fairly easy. If you suspect one (rough idle is one symptom), with the engine idling, lightly spray around the intake manifold and all the vacuum hoses.....with carb cleaner. If there's a leak anywhere, the engine will speed up. Avoid spraying the spark plugs and wires, as well as the exhaust manifold area.

You can pinpoint the exact leak with this method.....carb cleaner is flammable, so be careful.

[Benporat]

this thread from 2004 would have given you a short cut to finding the problem

http://www.focusfanatics.com/forum/s...ad.php?t=28249


thats how I found my problem:

http://www.focusfanatics.com/forum/s...&postcount=107

this looks like a very common, overlooked, and underdiagnosed problem
and some mechanics will run you up a big bill replacing perfectly good engine components before they get it right

[sunyfoci]

i replaced the hose behind the engine below the tb but im not seeing the second hose you posted pics of whereabout on the zetec engine is that located assuming it is on the dohc

[happy42]

Okay so i bought my first Ford and it was my 2001 focus ZX3 5 speed.Love it !!!!!!Lots of fun to drive then last week i did the "stupid" and ran it almost out of gas since then it has had a rough idle but also noticed about a couple days before that there was like a hissing/sssshhhhh noise.So i did some research and put gas treatment in then that didn't work so i got some trottle cleaner and cleaned the throttle body.That massde it run a little smoother now back to a rough idle at stop lights,like it's gonna die and rpms go down to about 750.
Engine light came on so went to the autozone and some 19001 code came about oxygen sensor.

I love my focus and of course the gas mileage and the zoom zoom of it.
so this weekend my son and i will try the z hose thing.But if any other clues plz let me know.