Rough Idle

[jobar]

Need some help guys, ive had an on going problem of a rough idle for some time now. My truck runs really rough at idle, but when I tap the gas the problem goes away. My steering wheel vibrates bad. I just had a tune up done 3 months ago, and haven't thrown any codes. I put a new o2 censor in and no luck. Any ideas?

 

[Winger]

I've been playing with this also. The first one a guy told me to check out was the Idle Air circuit on the throttle body clean it out really well maybe even remove it and clean the ports with some carb cleaner. That includes the Idle Air Control on the air cleaner box try and clean the two side by side ports they usually have a lot of black carbon looking deposits in them. You said this thing isn't putting out any fault codes? Weird. Is the RPM all of a sudden taking off to a high idle then droping off to this rough idle? Of course you want to look at you're plug wires even if theyre new there are some pretty cheasy ones out there that come apart the first time you pull it off the plug! I take my timing light and go from wire to wire and check for a miss in a particular cylinder then of course you can narrow it down from there! Good Luck!

 

[rangerpimpn84]

Well ive noticed with my 95 that cleaning the maf and iat sensor that it helped from time to time. I also had an issue with it missing and running rough and my exs dad told me to thro some marvel oil in the gas tank and in the crank case. suprise the combo of all of it worked fantstic. so good luck let me know how youre prob goes.

 

[dmassey]

Need some help guys, ive had an on going problem of a rough idle for some time now. My truck runs really rough at idle, but when I tap the gas the problem goes away. My steering wheel vibrates bad. I just had a tune up done 3 months ago, and haven't thrown any codes. I put a new o2 censor in and no luck. Any ideas?

I agree with the IAC being the potential culprit. You can check by disconnecting it while the truck is idling. The idle should drop even more or even stall (die) if the valve is working. There is also a impedence reading which I have forgotten but the disconnect test will give you a pretty good idea. Hope this helps.
Danny

 

[jobar]

I've been playing with this also. The first one a guy told me to check out was the Idle Air circuit on the throttle body clean it out really well maybe even remove it and clean the ports with some carb cleaner. That includes the Idle Air Control on the air cleaner box try and clean the two side by side ports they usually have a lot of black carbon looking deposits in them. You said this thing isn't putting out any fault codes? Weird. Is the RPM all of a sudden taking off to a high idle then droping off to this rough idle? Of course you want to look at you're plug wires even if theyre new there are some pretty cheasy ones out there that come apart the first time you pull it off the plug! I take my timing light and go from wire to wire and check for a miss in a particular cylinder then of course you can narrow it down from there! Good Luck!

I replaced the IAC just before the tune up. But, ill check anyways. When my foot is on the gas, it runs smooth. But, as soon as I take my foot off, the rough idle comes back and stays. It doesnt jump up and down, it just stays at a rough idle.

Im kinda wondering if its a fuel related problem. Mabey fuel pump, or filter. Can these cause a rough idle?

 

[AaronC47]

Sensors and rough idle

Just want to point out to you that where your sensors and such are concerned there is usually really big letters saying "NOT TO USE CARB CLEANER IN, ON, or AROUND in DIRECT CONTACT WITH MAF, MAP, or IAC, TPS or any other sensors" As damage can occur, there is a special cleaner for in and around the sensors and for the inside the air intake,

 

[TheTopher]

Im kinda wondering if its a fuel related problem. Mabey fuel pump, or filter. Can these cause a rough idle?

Fuel filter made a world of difference for my 95. The steering wheel stopped vibrating and the shifter barely vibrates anymore. Might want to check with whoever did the tuneup first though and see if they already did it.

 

[RangerFabWorks]

sounds like he has a vaccuum leak or two. take wd40 and spray over all the vaccuum lines. when the idle goes up, you have found a leak.

 

[jdm90]

Do you have a CEL at anytime?

 

[jobar]

Do you have a CEL at anytime?

No.

Ok, ive sprayed WD40 around all the vacuum lines that I can think of and, the idle went up on the line that runs to the intake runners. I found out that somehow the engine burnt a small hole in that line and I replaced it. The idle is still a little rough. My steering wheel is still vibrating quiet a bit. I checked the IAC and there is no carbon deposites that I can see. I checked with the guy who did my tune up and he said, that he didnt put a fuel filter in with the tune up. So im going to try replacing the fuel filter and see what happens.

 

[TheTopher]

Follow the guide in the technical library when you do, lots of good info in there. When I did mine I went to dump the filter and get all the last bits of gas out and a good portion of it came out brown.

 

[Winger]

Here's another suggestion

I took the vaccum line off of my EGR control and plugged it with my finger and and it smoothed right out..... So I thought it had to be the EGR Valve had another one around cleaned it up tested it with a screw diver and my finger over the vaccum port push on the plunger and place finger over the port and it held until I released the finger so should be OK theoreticaly.. Put it on and same thing. Looking like the EGR Vaccum Control Selenoid is the culprit! Picking one up in the morning keeping my fingers and toes crossed!!

 

[jobar]

I took the vaccum line off of my EGR control and plugged it with my finger and and it smoothed right out..... So I thought it had to be the EGR Valve had another one around cleaned it up tested it with a screw diver and my finger over the vaccum port push on the plunger and place finger over the port and it held until I released the finger so should be OK theoreticaly.. Put it on and same thing. Looking like the EGR Vaccum Control Selenoid is the culprit! Picking one up in the morning keeping my fingers and toes crossed!!

Let me know what happens.

 

[Bryan22]

sounds about right. If the actual valve was bad, unplugging the vaccum line wouldn't have made a difference.

 

[Resurrection Ranger]

I had a crappy idle for the longest time too. But it would act up more lugging the motor below 2 grand. But than i found out this amazing thing you can do. Its called paying attention when your putting new wires on. Apparently the #3 and 4 cylinder where swapped on the rear coil pack. I can't thank the technical library enough for having the diagram of the firing order and coil plug placement readily available. Drew it on a 3x5 card and went out to double check and presto problem solved!!
Hey, atleast I got myself a new MAF out of it. (I thought that would fix my problem at one point)