Contour Enthusiasts Group Archives Forums General Troubleshooting Rough idle in D and a hiss under dash

As the subject states, first I thought the problems were related. Does not seem so anymore.

Problem #1: the car vibrates really bad in D and R, turning on the A/C makes it unbearable. I looked at the accessory belt and it was noticeably flapping while in D. The RPM were going down noticably when switching between N and D. I did a search on this site (BTW, lots of great stuff, really helpful) and it looks like you guys would vote for the tensioner. I took it out today. Nothing obvious, perhaps the spring is weak. What are you guys recommending then? A new dealer part or a junkyard self-service? BTW, 4 months ago I did some work in the very same area: replaced a noisy idler pulley and the belt. Everything was fine for ~~ a month or so and then the noise in D started.

Problem #2: the air does not blow into the cabin, only on the windshield no matter what is selected (A/C or vent). A hiss can be heard from under the dash. Initially I thought my problem #1 was just a pirate air getting through a broken vacuum line. Nope. I blocked the vacuum grey line on the throttle - the idle speed does not seem to be affected at all. Does anybody have an experience with this?

95 Contour GL, AT, 76k

Vibration in gear is probably the driver side (holds the tranny) mount. They all seem to be going bad, all mine did. I found a note on a Ford mechanic BB about this. It gets droopy and the tranny bumps the engine carriage. If the engine sounds and feels a little rough when cranking the starter this is why.
Buy a new tensioner, springs got bad with age too. Especially if you are going through all the work of removing/replacing it.
Hissing is probably a broken vacuum line. System defaults to upper vents. It least it is giving itself away with all the noise. This could make the engine idle a little rough too. I would reset the computer after the fix to adapt to the mixture.

Here's another tip. My wife's 95 GL had the same problem with the air vents. It was a lever that came off of a vaccuum diaphragm under the driver's side dash. Put the seat back all the way, and lay on your back under the dash. Facing the bottom of the steering wheel, look to your left towards the center of the dash. You can see the diaphragm and a small vaccuum line attached to it. To help you identify the diaphragm, do the following: With the enginge running, emergency brake engaged, and the trans in neutral or park, get a helper to turn the air on and change the vent position selector knob. You will be able to see it changing position. You will also see the lever near the top of the diaphragm. It should clip onto a threaded plastic piece on the top of the diaphragm. You need to thread a new nut and washer on it to keep the lever in place, (can't remember the size). Hopefully this will help you out.

I second johnchalk's opinion on the air vents. My 95 GL has done it twice now.

The thing you're looking for is just above the accelerator pedal and looks (a little bit) like a miniature beer keg. Should have one red and one yellow rubber line coming off of it. The plastic bit on top moves up and down when you change the air position dial, and it if it is not attached to something, it should be. I believe it can just be snapped into place, however.

good luck.

You can definitely just snap the lever in place. But, since the plastic piece on top of the diaphragm is threaded, put a nut on there. It won't come off again. Ford wanted $100.00 to do what I described before. You just know that they had encountered the problem before and were trying to make a quick buck. My poor wife went through a summer before I had time to figure the problem out.

Many thanks, Guys! The trick with the "keg" under the dash worked 100%. I just can't believe that Ford would release such a design...

I put a brand new tensioner and the vibrations are a lot less worse ;-) I would say there is a 60% improvement, but still I can feel the RPMs going down in D. Perhaps they are going too low but I have no way of telling (my instrument panel has no tachometer). Any ideas how I can verify the RPM@idle? Is there a test point?

I am also looking at the DR side engine mount, as suggested above.