I have a 91 or 92( the sticker on the side of the door says it was manufactured in 91) 626 DX and every time i start the engine when its cold the engine idles at about 2500 rpms then it goes down and stays at 1500. This kills my fuel economy, any ideas on what could cause this. Also, when its warming up the idle jumps up and down.


-by the way im new to the site(not that anyone cares)
-solid

 

An easy one to try is to replace the PCV. Look on your valve cover, there should be a small object connected to a tube going into the valve cover. Pull that thing out and disconnect it from the tube. Get a new one and reinstall.

Here's one I found with a quick search ($8)

http://replacement.car-stuff.com/par...howdc=true#top

 

I did think of that this morning, but when i tried to take it out and check it if rattled, i couldnt get the damn thing out. Im gonna have to wait til tomorrow to change that out. Thanks for the feedback.
-just to be sure, pcv its the one that goes to the intake manifold right. Not the one that goes into the the air intake hose, right?
____________________ ----------------legend:
[..................................]------1) leads to intake mani
[..[1]...................[2].....]------2) leads to intake hose
[.........{3}....................]------3) oil cover
[______velve cover____]
----------front of car------ (note:disregard dot in diagram, needed tem just so the diagram would collapse.)

 

Not sure on your exact application...Every PCV I've dealt with was installed into the valve cover (not the intake) I usually work on 8-cyl engines though.

It should look like the pic in the link if yours is a 92 626 with 4-cyl.

 

no it is...its just that this valve cover has two tubes going from the valve cover. one of them leads to the air intake hose, and the other one leads to the air intake manifold. After looking at my car(and the pic) i've determined its the one that leads to the manifold.(its a bitch to get that thing out.)

 

alright, i change the PCV valve and my fuel economy has sky rocketted almost 50%. However, when the car is cold, i still get that rough idle. It jumps up and down. Any more ideas on what it could be?

 

my Mazda 6 is doing the same thing and I took it to the dealer ship and they told me that I had a hole in my PCV hose make sure you don't have any holes on your vaccum lines......

 

Possibly a bad motor mount. If vibration is felt at the steering column, then it probabaly is the motor mount. Engine misfire as well as a dirty idle control valve is another thing to consider.