surging/rocking while idle

93 Taurus - surges/rocks and runs rough while in idle and at slow speeds! (and frequently stalls while idleing, unless I rev it in neutral.)
- headlights flick on and off while driving after 15 mins.
- engine light stays on after driving for 5 mins, even though I've gotten it fixed 6 times recently.
- wipers won't turn off after being turned on, unless I shut my car off.
All these problems started only about 3 months ago. Anyone else experience similar problems?

My car is a 95 and also has a rough idle. It feels like it is going to stall while sitting at a light. The temperature gauage also starts to go up while sitting in an idle positon probably caused by my head gaskets going. Also while idling my interior lights flicker to the idle which is odd.

I just started having this problem this morning. Feels like it's not getting enough gas at idle speed. Nearly dies. Friends suggested cleaning the fuel filter/checking the fuel pump. I've read elsewhere and some people point to changing the head gaskets. Anyone figure it out yet?

Clean the intake plenum and idle valve with Gumout. You will see black crap all over the inside of the intake. Do this while running, try not to let engine die.

I have had similar problems with my '93 taurus. Several people here told me to change the idle air control valve, with no effect. My car still idles high and low. Sometimes it stops on cold mornings, but as soon as the engine warms, it begins again.

Also, I have recently run into a similar problem with my wipers. When it sprays washer fluid, the wipers will not cut-off. I have to turn off the vehicle to stop them. This began about 4 months ago. Now, almost every time I turn the wipers on (low, mid, or high delay), the wipers act as if they are on the high setting (however they will still turn-off, for now).

I hope someone has an answer out there.

Since you have a '93, I almost certain that if you take the intake hose off the throttle body and look inside, there will be a bunch of black crap all over the throttle plate and surrounding area.
If you carefully clean this off without damaging the plate or soft aluminum around it, I bet most of your idling problems will go away. You will have to completely take off the throttle body to do it right and not get crap in the plenum, although that is probably dirty too.

I had the same idle problem on my 93 3.0L Taurus. I changed gas filter, spark plugs, plug wires and cleaned the idle air control valve. Nothing happened. Then I went to Auto Zone to have my generator and battery checked and I noticed that I had a very low idle rpm, around 500. I just adjusted the idle rpm screw a few rounds and now the problem is gone.

I had the same idle problem on my 93 3.0L Taurus. I changed gas filter, spark plugs, plug wires and cleaned the idle air control valve. Nothing happened. Then I went to Auto Zone to have my generator and battery checked and I noticed that I had a very low idle rpm, around 500. I just adjusted the idle rpm screw a few rounds and now the problem is gone.

Well, you didn't fix a darn thing, you merely bandaged the problem. In fact, you probably complicated things. Now the throttle position sensor is never actually at the original idle position. In your post you didn't mention cleaning the throttle body. Take off the air cleaner hose where it attaches to the front of the intake plenum. You should see the throttle butterfly. Clean the hell out of this. Better yet, take it off. It only has four screws and maybe some linkage. Get all that black stuff off.
If you do this, I almost garantee that the idle will be excessive since you adjusted it up. I have done this many times. I once bought an '87 Sable that would not run worth a crap. I cleaned the throttle body. Then the idle was extremely high. The previous owner did what you did. Now I had to adjust it down and pray I get near the factory setting.

Take off the air cleaner hose where it attaches to the front of the intake plenum. You should see the throttle butterfly. Clean the hell out of this. Better yet, take it off. It only has four screws and maybe some linkage. Get all that black stuff off.
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Thanks for the reply. If I have time left to do that and it turns out to be really that problem, I will clean that thing with pleasure, but I don't think that anything is dirty, because I just managed to make over 28 miles per gallon on the highway. I will take a look at this anyway next weekend.

Milage may or may not be affected, since at highway, the throttle is open quite a ways off idle position.

Milage may or may not be affected, since at highway, the throttle is open quite a ways off idle position.


Hello, I just cleaned it with carburetor cleaner and really, the idle rpm was way higher... is there a sensor that gets clean? I mean, the throttle plate is just a plain peace of metal and the dirt wasn't really existent, so few that I thought it wouldn't make a difference...but it did.

There is an Idle Air Control (IAC) servo that allows air to flow around the throttle plate at idle. This IAC servo uses small passages in the throttle body, and you likely cleaned these passages in the process, allowing more air to flow around the throttle plate. Also, the cleaner may very well have helped clean the fuel injector nozzles which would make a difference as well.

Often times the rough idle problems can also be helped out by running a bottle of fuel injector cleaner through the system. When I worked at my parent's shop, we always put a bottle of injector cleaner in with every oil change. Numerous times new customers would come back or call asking why fresh oil would cause their car to run so much better. I continue to put a bottle of injector cleaner in the tank every time I change my oil.

-Rod

Often times the rough idle problems can also be helped out by running a bottle of fuel injector cleaner through the system. When I worked at my parent's shop, we always put a bottle of injector cleaner in with every oil change. Numerous times new customers would come back or call asking why fresh oil would cause their car to run so much better. I continue to put a bottle of injector cleaner in the tank every time I change my oil.

-Rod


Do you mean fuel injector cleaner together with engine oil ??? How does that work to clean the injectors? Doesn't that alterate the viscosity of the engine oil? I always put a bottle of injector cleaner in the gas tank...by the way: which one would you recommend? There are so many, I can't really see which one I should by, so I just keep with the cheapest from Wal Mart, several around 93 cents, including STP.

Do you mean fuel injector cleaner together with engine oil ??? How does that work to clean the injectors? Doesn't that alterate the viscosity of the engine oil? I always put a bottle of injector cleaner in the gas tank...by the way: which one would you recommend? There are so many, I can't really see which one I should by, so I just keep with the cheapest from Wal Mart, several around 93 cents, including STP.

He just means that while having tools out and taking the time to do an oil change, go ahead and dump some injector cleaner in the gas tank. It helps one to remember to do things periodically, like the oil change.

Glad you got the throttle body cleaned, I am sure you have already tried to adjust the idle back down. As a side note, my wife's 2001 Taurus actually had a problem with the throttle wanting to stick closed and when you put enough force on the pedal to break it loose, it lunged forward. The cure? I cleaned the throttle body and throttle plate. There was alot of black crap on it already. Only had about 30,000 miles on it.

Right, as Got3Fords mentioned, the oil change is about the proper interval to add injector cleaner to the tank. An oil change is part of routine preventive maintenance, as should be injector cleaner. Why not do it all at the same time.

I too buy whatever is cheapest. I haven't noticed a significant difference between the brands. Plus, if you are adding it on a periodic basis, even if the cheap stuff is less effective, it shouldn't matter as you will be using it regularly enough that there won't be many deposits.

Got3Fords, I had the same symptoms on my SHO as your wife. It never bothered me until last winter when I couldn't keep from spinning the tires accelerating from a stop. The carbon on the throttle plate was malleable enough that when I'd let off the gas, the sludge would wedge the throttle plate closed. I cleaned the plate the best I could and the problem went away.

Fortunately (?) a couple months later one of the rear coil on plug coils went bad (The 3rd Gen SHOs have one CoP for each of the 8 cylinders) so I was able to easily clean the back of the throttle plate and inside the intake runners while I had the intake off to change the rear CoPs and plugs.

-Rod

Got3Fords, I had the same symptoms on my SHO as your wife. It never bothered me until last winter when I couldn't keep from spinning the tires accelerating from a stop. The carbon on the throttle plate was malleable enough that when I'd let off the gas, the sludge would wedge the throttle plate closed. I cleaned the plate the best I could and the problem went away.
-Rod

What is up with that? A newer car shouldn't have these nuances. I am seriously thinking about re-routing the crankcase breather hose to keep it from depositing all the crankcase crap on the throttle.

I figure the previous owner just didn't drive it hard enough. At least that's the story I tell my wife, and that's why I drive it the way I do. :)

-Rod