I own a 1995 Ford Explorer Eddie Baurer 6 cyl/4liter

I have never had a problem with it (120,000) runs like a top. Recently I had a tune up. New plugs, wires, new ERG? (silver disk attatched to exaust manifold)
Sprayed out throttle body too.

Now it idles worse than with the orignal plugs.

What it does is idle at 1400rpm then it surges up to 2000 then down again. it seems to be linked to the alternator. When the alternator clutch kicks in the rpms jump up then back down to 1200rpm. Same thing happens when I put the defrost on. I can hear the alt. click in and the rpm jumps. This happens at idle in drive while holding the brake I can feel the engine surge. If I let go of the brake it will go maybe 7mph. Then it idles down and all is well. I don't remember it doing that before the tune up. Had it back twice and they found nothing.

I replaced the TPS (per this forum) and it did seem to smooth out the idle somewhat and slow down the surges, but it still does it.

I guess when the alternator kicks in the engine needs more gas to keep idle smooth. The trouble is it seems to give too much gas. Its about a 600rpm jump.

I don't like torque bracking the truck or slamming into gear at 2000 rpm.

Adjusting the throttle stop did little. If I raise the base rpms via the throttle screw to 1600 it seems to slow the surges. I would rather have 900rpm idle though.

I have a IAC on order, hoping thats it.

I noticed when I removed the TPS that it had a silver probe type thing screwed into the throttle body. I wonder if the degreaser messed it up when I cleaned the inside of the throttle body.


Any ideas?

We'll see if the IAC helps.

Maybe a manifold leak?

try resetting teh computer and also it is the compressor clicking not the alternator i would also get another iac and check for vaccum leaks

Billy is correct, alternators don't "click in", they run whenever the engine is running. Clicking is the ac compresser clutch engaging.

As for the crappy idle, did you replace the plugs yourself? Check and make sure all the gaps are correct. Make sure the wires are not touching and arching. Make sure each wire from the coil is going to the correct plug.

When you throw on the new IAC, clean the MAF sensor too.

ya i forgot they are different plugs for the sohc and ohv but i can't see why they would cause a fast idle

The thing making the clicking is on the drivers side just behind the radiator. I thought it was the alternator.

The plugs have been changed twice and gap checked. My old gap was like 2x what it was suppose to be. The 120,000 really eroded the electrodes.

I will check the wires again.

I had a shop do it. All they did was put the idle up to 1700 and said it idles smooth. LOL. Yea but its just a bit high. If I take the throttle screw and set it so the idle is low, it will go to 1000 rpm but then it really does the surge thing.


What is the MAF sensor? and where is it located?

Thanks!!

the MAF (or Mass Air Flow) sensor should be located near the air filter...it will be in the air intake hose going to the engine...it would look like a break in the hose with a clamp on both sides...hope that helps ya...p.s. be careful taking it out, as it can get dirty very easily if ya touch it...if the wires are attached, I've heard that touching the MAF without touching other metal first with your hands can short it out...no need replacing something that might not be broken before ya messed with it, but with 120,00 miles, some electric stuff is bound to go out sooner or later...it's good to look at a manual somewhere (possibly located here somewhare) on how to clean this part and/or replace it.

Thats for all the help guys, this is a great forum!

I will let you know how it goes.

One more question about idle. How exactly is one suppose to adjust the idle rpm? Its not the throttle cable, I tried that and the computer seems to override it.

You can't adjust the idle manually, it's done by the PCM.

If the engine just about dies, it is an electrical problem causing the IAC to open and cause high rpm.

A poster had that problem last week and I had him measure the resistance of the white wire to ground with the IAC connector unplugged. He said it was shorted. He unplugged the cable at the computer and put it back in. The short was gone. Evidently a strand of wire was shorting. There is also an engine bulkhead connector that might be shorting.

Bad news on the IAC. I picked it and found the electrical connector had changed. The replacement one is smaller, thus I can't plug it in.

I notice there was not a gasket on my old IAC. I put my old one back on with a new gasket then I cleaned the MAF sensors.

On the MAF I could not remove the sensor itself as Ford put glue in the star screw hole. I was able to put a Qtip down the little tube and clean about 60 percent of the elements surface.

I then adjusted the throttle stop down to see if it would idle lower than 1600. The massive surges in idle seemed better but at around 1000 rpm the engine starts to chug, likes its either missing, or a clogged injector.

At 1200 rpm its smooth as silk. Wonder why it chugs at low rpm?

I checked for plug wires arcing (dark garage, lights off) saw no sparks.

Reset the cpu via pulling the neg batt terminal.

Still no good.

At least I can put it into gear at a lower rpm but I would like to figure whats up with the idle.

I guess I could get a new IAC from Ford parts, that should fit.

Is it possible a plug wire is mixed up? I assume it would run poorly at any speed if that were the case.

Follow up to my rough idle post.

Here are the things that I have done or had done.

1. New IAC
2. Cleaned MAF
3. New TPS
4. New copper exhaust intake thingy with silver exahaust sensor. The shop broke original copper pipe and charged me an arm for a new one.
5. New Plugs and wires


I have smooth idle at 1200 rpm but If i adjust the throttle bottle screw to bring rpm lower to 1000 it starts to idle rough.

I guess I will call it good for now, unless someone knows of something else to try.

Thanks..

I think I know what the problem is.

Last week my engine had a high pitched sound comming from it. I thought it was a bearing, it turned out to be an air leak or vacuume leak somewhere.

I took it in and the guy did not have enough time to find it.

Its very high pitched like a dog wistle and changes a littel bit with some throttle. Its loudest at idle and goes away with more gas.

I think it could be comming from inside the top manifold. There is a tire pressure type gauge on the side of the engine. Its not the airconditioning, anyone know what its for?

And suggestions on finding the source of the leak? That must be why my idle has been erratic for the past few months.