Nissan Frontier Forum banner
1 - 9 of 9 Posts

·
Registered
Joined
·
25 Posts
Discussion Starter · #1 ·
Ok guys, I just developed a "bump" per say when the truck is at idle. It only seems to do it when the ac/defrost is running. The first time I felt it, I thought someone lightly tapped me from behind. Any ideas?
 

·
Registered
Joined
·
2,326 Posts
Engine missing on one of the cylinders? Or could be a sticky brake once you let off the brake and step on the gas it will let loose? Could be a distributor going bad. I've heard of first gens losing the bearing in the lower part of the distributor and as it goes bad it engine has a tendency to do erratic things.


Pull codes to find out.
 

·
Registered
Joined
·
25 Posts
Discussion Starter · #3 ·
Engine missing on one of the cylinders? Or could be a sticky brake once you let off the brake and step on the gas it will let loose? Could be a distributor going bad. I've heard of first gens losing the bearing in the lower part of the distributor and as it goes bad it engine has a tendency to do erratic things.


Pull codes to find out.

There isn't a light. Been doing some more searches online, and it looks like it could be the idle air control.

Now I just need to find out what it looks like and where it is so I can clean it and adjust.
 

·
Registered
Joined
·
25 Posts
Discussion Starter · #4 ·
Ok, I am still having a little bit of trouble, here is a little more info:

About a month ago I changed the valve cover gaskets, replaced the plugs, pcv valve, and fuel filter.

I don't remember the problem starting until after I did all of that. I have checked and rechecked to make sure everything is tight and that everything is connected.

At idle, sometimes (you have to sit for a minute or so) with the brake pressed and the ac/defrost on the truck will stumble. The idle will drop a good 300 rpms or so, and it can be felt pretty good in the cab. Feels like someone lightly tapped me from behind.

I can't seem to get it to do it with the ac/defrost off. I don't have any codes, except for the KS which I always have had (no S/C). The truck runs great otherwise.

Also, I have also noticed lately, that when turning the knob to defrost or any other settings, that the flow is still coming mainly from the front vents. I am not sure if this is connected, or just a coincidence. Also, the truck doesn't seem to idle up when the compressor kicks in.

It is really starting to get under my skin, and I am clueless! Any ideas?
 

·
Registered
Joined
·
25 Posts
Discussion Starter · #5 ·
I was readying the Haynes manual today at lunch, and it looks like the Fast Idle Solenoid by the IAC is what regulates the load of the AC. The fun part? Well they are both under the plenum. What was Nissan thinking?????

It says in the manual that when you jump the solenoid to test it, it will "click". Everytime the AC is on, and I have little burts of low idle, there is a clicking noise. So I imagine it is working, just not correctly?

I really don't want to have to take the Plenum off. Are there any wires a little easier to get to in regards to the IAC and Fast Idle that I could check first? Also, what fuses run these?
 

·
Registered
Joined
·
80 Posts
If you figure out what it is, let me know, Mine just started doing the same thing today, and it's allready driving me nuts!!
 

·
Registered
Joined
·
24 Posts
A little thread necrophilia. Has anyone else ever had this and found a root-cause? My truck (an '01 CC) has begun doing this same thing. No codes/events appear on my OBD II scanner.
 

·
Registered
Joined
·
1,223 Posts
You sure it's not the AC Compressor activating?
 

·
Registered
Joined
·
24 Posts
Yep. Already checked that. Still looking for vacuum leaks, etc... This symptom presents itself as an irregular and non-rhythmic 'stumble' at idle. Very noticeable.
 
1 - 9 of 9 Posts
Top