Rough/Erratic Idle?????????
 

Like the signature says, 88' Ranger Supercab, 2.3L, 4x2, 5sp, 114k. When I first start-up in the morning, it starts right up, and dies 5-10 sec later as the idle drops (clutch in, no foot on the brake). If I give it just a little gas right after it fires up I can keep the idle steady. If I don't let it run for a few min it will die when I back-up and apply the brakes, unless I keep the revs up. After it is warm and I am sitting at a stop the idle will be smooth for a few sec, then stumble for a few sec over and over. It has not been cutting off during stops, but it drops pretty low. It runs just fine while driving, the only problem I hear from the engine is when I step on the gas while going up a hill it will knock a bit. As long as I don't press the gas too hard it won't knock at all. After replacing the leaking tank, and shot trans, I am averaging 23-25 mpg over the last 3 fill-ups. My first thought is that I have a vacuum leak or something, but I don't know where to start. Or should I be looking at something else?

Just to list what I have replaced (previous owner replaced several things too, but I don't have the list):

Transmission (rebuilt from ManTrans)
Gas tank + straps (tank cracked during the winter)
Fuel level float
Fuel filter
Idler pulley + both belts (pulley broke off)
Heater hoses
Front brake pads


This is the same truck I have been battling with every month or so when it breaks down, as some of you may have seen my older posts. Some of that list won't matter for the problem I have now, I just would like to know a good place to start.

There are more than a few possibilities: For one, the fact that it knocks while climbing tells me it could be the EGR valve and/or it's electronic control. I'd take off the EGR and it's exhaust tube and clean the carbon out of them (don't get any cleaner on the diaphram in it or it will eat it up). While you have it off and cleaned try blowing through the egr valve. It shouldn't let any air pass unless vaccum is applied to the little port. You can also try testing it with a vaccum tester (rent one free at an auto store). Put the proper load on the little port and see if it holds that load for a minute or so. I'd also clean the MAF with some EFI safe throttle body cleaner. Next, clean the throttle body. Is it fuel injected? If so, use EFI safe cleaner on that and take a soft scrub brush and brush out the carbon as well. Still have a problem? Next check the IAC as it can have carbon build up on it. An 02 Sensor is also a candidate to replace if it's got more than 30 or 40 thousand miles on it. Put a bottle of injector cleaner in the gas. Beyond that, the throttle position sensor could have some dead spots in it.

Yes, EFI. I think they quit using carbs around 85' or so...???

I don't know. I am the 3rd owner of this truck (114k now). The first owner had it about 15 years, 2nd owner had it for less than a year. I don't think he was too interested in trying to fix the trans. I bought it for cheep because of that bad trans.

I can check some of those things this weekend if it doesn't rain like mad. We get alot of rain during these months. Any other ideas folks?

At the risk of sounding like a fool.... I am having a hard time identifying some of the components mentioned above. What I think is the MAF is this thing that looks like a solinoid on the side of the air box between the box and the fender. Haynes is not much help.

I can,t seem to find the EGR valve too. I am looking around the FPR and intake manifold. Haynes is not much help here either.

TB, yea.... I got that one covered. Although, I am wondering if taking it off to clean it would be easier?

And as far as the IAC, I can't find it in the manual, and I am not even sure if my year has one.

Part of the problem is the rain that has been falling steady all day since 10am. Sucks not having a garage yet. Can anyone help identify some parts.

Now, I have the same motor but it's a 94 Ranger so you may be lacking some of these parts. The best way to identify them would be to get the Haynes or Chilton manual specificly for the Ranger, found at most auto parts stores. The MAF sensor should be on the intake hose right after the air box. It will have a harness going to it. The IAC is a cylinder shaped object on top of the engine at the back, hitched up to the throttle body. It also should have a harness going to it. The EGR valve is is round and somewhat flat, found also at the throttle body. It will have a vacuum line hitched up to it and a metal tube that goes down to the exhaust near the 02 sensor. You can also check the tech articles on here and other sites that should have pictures of these and how to clean them.

I don't think you have an EGR but I could be wrong.

I have a Haynes manual already. It is worthless in some cases. As far as I can tell I don't have a MAF sensor. I am not even sure I have a IAC. If it is connected to the TB, then I have only one electronic hook up, and I don't think it is it. I did find the EGR valve. On mine it is in the back of the engine bolted to the side of the intake manifold. I will put an update below on the current progress.

THE SAGA OF THE "TOP END" MINI OVERHAUL

Ok, so here is what is going on after a full day of turning wrenches. The following is a list of parts I am replacing:

PCV valve + rubber hose to mainifold
Distributor cap and rotor
Spark plugs and wires
Ignition coil and part of Ford harness that was damaged during previous posted problem
Air filter
EGR gasket
Valve cover gasket
Intake manifold gasket (middle one)
Throtle body gasket
Various hoses

I started to tear things apart, and one thing lead to another.....sorry this is so long. I took out the air box to look at the solinoid on the side, and to clean it out. This is what I found, I still don't know what it is??? Anyone? It was dirty inside, so I tried to clean it, and the air box. I hope EFI cleaner dosen't hurt it. Oh, and I don't know what those vaccum tips on the top are for???
http://img65.photobucket.com/albums/...de_air_box.jpg
http://img65.photobucket.com/albums/...op_air_box.jpg
http://img65.photobucket.com/albums/...ox_removed.jpg

Then I moved on to the spark plugs and wires. I removed the plug closest to the front (#4 I think), and it looked dry and powdery white. Not too sure what that means??? I think the Haynes said, weak ignition, running lean, or vaccum leak. They will be replaced, but I would like to correct any issues that caused this. Then I am replacing the ignition coil, and part of the coil harness that had broke afew months ago. And the cap and rotor. I haven't looked under the cap yet to see what signs, if any, are in there.

Then I moved on to removing the TB, and the upper part of the intake manifold. This is when I found the EGR valve on the back of the intake. The lower part of the manifold had a "wet" black look in the runners. Oily carbon deposits I guess. The upper manifold was packed full of crap too. The hole that leads to the EGR was only about 1/2 the size it should be. And the back of the TB, looked like an Oreo cookie, and almost as thick. There was so much build up on the back of the TB butterfly, I am surprised it ran at all. A can of Valvoline SynPower TB cleaner (this stuff works!), some towels, old tooth brush, and flat head screw driver did wonders. The TB looks new on the inside, and the intake needs a little more TLC, but I am getting it out slowly. I hope opening up the EGR inlet, and cleaning the butterfly will help alot.

While the manifold was off, I decided to try to correct the upper oil leak. So I removed the valve cover too. The bolts were fairly loose, and there was ALOT of build-up around the cover, and exhaust manifold. I did what I could there, and sanded the head edge down with emery cloth to remove old deposits. The worst was the valve cover gasket. I am not sure if it was the original or not, but it was so hard it was like a rock. A razor and wire brush took most of it off. A drill and wire wheel took the rest off. I did notice a small pin hole in the corner where the valve cover goes over the front "hump". I am only guessing it is not supposed to be there??? I got some JB kwik for it, I hope that will work. Something else I noticed is one of the head bolts in the oil valley had alot of hard carbon build-up. I don't know what it is from, so I just pulled it out???? As a side note I noticed the wear marks on the cam. Does this look bad for 114k???
http://img65.photobucket.com/albums/...C/camshaft.jpg
http://img65.photobucket.com/albums/...shaft_wear.jpg

I also found the PCV valve right behind the alternator. It was soo covered in crap that I didn't even notice there was a valve in the middle of the two rubber hoses. Does anyone know where the lower half of the hose goes from the bottom of the PCV???

I just hope I can get it all back together tomorrow. I am still missing some 11/32" hose for the coolant overflow hose to resivior. Auto parts store didnt have any. Doh!

The cylinder on the air box is you IAC. The vacuum connections are for the warm air valve, I'm not familar with the layout of the 4 banger but it should have a line from the intake manifold and another going to the control valve which should be in the pipe shown in your third pic.

Thanks Ken, I was looking through my Haynes again last night, (late so I can't be sure of what I saw) and I thought I found a picture of the thing on my air box. I think they called it a "Air Bypass Valve"... whatever that is??? It was in the Emissions section where I hadn't looked yet. I am still thinking I don't have a IAC :-huh And the 2 vaccum lines seem to run down under the battery right in-front of the air box. I am only assuming that they control the valve for the air that comes in from the heater tube looking thing that runs from under the battery to the exhaust manifold????? Which looks like it broke off the exhaust side years ago.

I have a big update (with pics I hope) to post in the next day or so. I basically tried to clean everything from the airbox to were the head meets the manifold. I do regret not getting a pic of what the back of the TB looked like. I wasn't kidding about the Oreo thing. :-huh

The ABV and IAC are teh same thing. The warm air thing is no big deal unless your in someplace REALLY cold, just make sure the port at the intake is plugged.

Ahhh, I see. That would make sense..... Ford messing with my head giving something 2 or more names. :-X09 Not the first time this has happened.

Well what ever it was, I took it off and tried to spray it out with solvent. It was not great, but I didn't want to damage it.

The IAC can be disasembled, clean the valve portion real good with solvent/brush, not the solenoid part.

THE SAGA OF THE "TOP END" MINI OVERHAUL Part2

So here is what is going on after a 2nd full day of turning wrenches. Success!!! Well, I call it a good day when I get it back together, and it fires up.

Anyway, I started at the air box, replaced filter. Then I cleaned the IAC, or ABP, what ever Ford calls it. I didn't realize it can come apart like Ken said. I didn't see how, but it is easy to get off, so I will look at it again. Here is the airbox with the vaccum lines on it (ABP is under the plactic cover):
http://img65.photobucket.com/albums/...IC/Air_box.jpg

Next I removed the TB, EGR, and top of the intake. What a mess! I wish I had pictures of it, but I was far too dirty to use the camera. I cleaned the crap out of the TB, and tried to clean out the in and out of the EGR. I didn't use any solvent on it (I was too scared to damage the valve). I didn't clean the exit tube from the EGR. I forgot about it, until I was ready to put it together. I was not sure if I could spray solvent down the tube (might damage the cat???). Then I cleaned out the upper intake.... yuck! There was alot of build up around the EGR port in the manifold. Replaced the gasket on the EGR, and the bottom of the TB. I also replaced all the hose on the manifold and the PCV.
http://img65.photobucket.com/albums/...front_side.jpg

Possibly one of the worst issues was the valve cover. Caked with oil, dirt and junk. All the bolts were loose with oil leaking out the sides. The gasket was so hard I had to use a razor and a wire wheel on my drill. While I was cleaning it up I noticed a small hole in the conrner of the cover. I think it has been there along time. The best I could think of was JB Kwik Weld. It was in the corner near the timing cover.
http://img65.photobucket.com/albums/...BKwik_weld.jpg

The blue line you see is a FelPro rubber gasket with metal seals around the bolts. Seemed to fit pretty good.
http://img65.photobucket.com/albums/...ver_gasket.jpg

As I mentioned in a previous post, I found a lot of carbon build up around the head of one of the head bolts in the middle of the oil valley. Anyone know what this is from? I put the new gasket on after sanding the head lip and torqued it to the proper spec.

Since I left the lower intake manifold on, I couldn't fully clean it. I did try to wipe it out and spray solvent down the runners. I figured it is flamable so it would burn off..... I don't know if that was a bad idea. I also found where the lower PCV hose goes, but I didn't see any way to change it with the manifold on. Anyone?

Changed the plugs, wires, coil, cap and rotor. Gapped and torqued the plugs, then ran the wires throught the wire looms. All of my old plugs were dry and powder white. (pic will have to follow since I can't seem to upload right now)

I put the manifold back together with the FelPro kits I got, torqued it and connected all of the new hoses. I also re-ran my heater hoses with the new 3 way fitting I had to get from the dealer
http://img65.photobucket.com/albums/...right_side.jpg
http://img65.photobucket.com/albums/..._left_side.jpg

I left the coil unplugged to crank it for a few sec to blow the solvent through. After I connected it back up, it took 2 tries but it stumbled through the excess and it smoothed right out. Woohoo! It was running. Now it starts right up and accelerates much stronger. It still pings/knocks a bit under hard acceleraltion or up hill. I don't usually drive like that, but I had to test it out. It is not as bad as before, but still there. It also seems to idle much smoother. To me it seems a bit high, I don't have a tach??? On another positive note my pressure gauge seems to stay just on top of the L. I think the valve cover hole patch and new gasket helped some. :-X22 It is still lower than I would like. I guess a new oil pressure sensor + pump will be in order when I do a lower end mini overhaul. :)

These are the pics of the old plugs: Does this tell anyone anything????
http://img65.photobucket.com/albums/...d_plugs_01.jpg
http://img65.photobucket.com/albums/...d_plugs_02.jpg

I don't know if Ken feels like moving these up inside my post above where I mentioned them???