My car ran perfect on Sunday. On Monday morning, I started it up, and immediately it was idling very rough. This has never happened before in the 20 years I've had the car.

I drove it about 50 miles today on normal roads, and it drove fine. The only issue is that it idles rough.

Any ideas for what I can check myself before I take it to the garage?

Thanks,
John

 

Vacuum leak you can check yourself. Look for a hissing hose underhood.

 

Check the choke on the carb, then check your contact points on your dist cap. Possible problem with o2 sensor. Good luck.

 

Vaccum leak and check if your getting a good flow of fuel!

 

Ok, I found a small hose that was detached near the windshield. I reattached it, and that fixed it. It idles perfectly again.

I'm attaching a picture of the hose, what is this???

Thanks for your help!!!
-John

 

whoo hoo!
Doing my happy dance! woot, woot!
Called it, called it!!!
haha, I just like getting the right answer.... Wish my profs would agree with me more often...
I think that's for HVAC stuff.

 

Haha..ok..cool...I'm happy it's fixed...

But how does a detached HVAC hose cause the rough idle??

 

It's still a vacuum line, with it detached, the motor got a schwack more air than it needed, without the fuel to match, so the idle went to hell.

I've heard that some HVAC units on these cars require a vacuum source to power it sorta thing. Helps keep certain ducts open in certain positions or something like that. I've never seen it on my car, so I can't say.

But a vacuum line on the firewall, driverside, in that place, sounds like HVAC to me.