unsteady idle engine idles bad bad idle 1989 pathfinder

[rjfortuna]

Here is what I did to fix my issues. I am not a certified mechanic so at your own risk.

 

I bought a 1989 Pathfinder. It was revving up and down varying about 400 and was idling at around 1500 when cold.

 

This is obviously not right.

 

I had to track down various vacuum leaks. The primary one I think was causing the issue was the pipe that came of the cat. Converter. It has a flexible tube there that connects the 2 hard lines. This feeds back into the engine as part of the emissions control.

 

I found some 3/4 inch Silicone line. It is high heat resistant and has worked. You can find it at rubber and gasket stores and some older muffler shops. Use hose clamps and it will work fine. Expect to pay anywhere from 2.50$ a foot to 7$ a foot.

 

My charcoal box was just GONE. It allows a vent from your gas tank and pipes the fumes to the engine to be filtered and burnt off. This looks like a coffee can when its there. There are 2 larger lines that went to mine and 1 smaller one.

 

Put a screw in the small line closing it up and I plugged up the other larger lines and it helped immensely.

 

I found that under the a.b. valve (weird mushroom shaped deal in front of the carb) had a bad split in the vacuum line underneath it as this valve gets horked on and pulled every time that someone takes the air filter box off the carb.

 

Fixed that cracked line.

 

It idled smooth at that point. I found the idle control screw under the left front of the carb and turned it down. Make sure you have the AC on if you have that option to be sure the vehicle is idling correctly when using that feature.

 

That fixed me. Good luck.