97 Taurus running ruff at slow speeds

[Northlander]

My wifes car is running ruff. I put some Seafoam in it and that didnt do the trick. Its only at slow in town speeds and still shifts and cruises well.

Air or anyone else have any ideas? Fuel Filter? Where is it on a 97 Taurus? The plugs and wires look ok. Only 56,000 on it. Mostly in town to work miles.

Any help appreciated. Thanks.

[Jeremy airjer W]

Its a 3.0 OHV pushrod driven over head valves. That shoots my theory down the tubes!!

[Northlander]

Dropped it off this morning and Im just waiting to see what codes they come up with. Should I do the plugs, wires and distributor cap now while its in? Air Ill just call ya.

[Northlander]

Turned out to be a misfire in 1 and 5. Also something with the cam but we just did a tune up and hopefully the new plugs and wires will do it. Mechanic thought that the bad wires may have brang up the cam code? Insight on this anyone? If it turns out to be the cam deal what do you guys think it will cost me? This set me back $130.

[Macgyver55]

This is what I suspected (plug wires)as I said earlier in the thread. If I remember correctly 1 and 5 are next to each other in the firing order, so although doubtful it could possibly cause a fluke code. Lets hope this is the last of it.

[Capt. Don*]

Did they give you an invoice which included the comments from the mechanic, I would hope the codes and the order they occurred would have been on there. The cam thing you speak of, for it to be brought up there must of been a code associated with it, do you know what it was? Without getting too technical I can tell you there is no way on earth that the misfires could of set a cam sensor code, the cam sensor and syncronizer control fuel injector timing on that motor, not ignition. It will most notibly affect the way the engine runs primarily at low speed or at idle in gear. It most likely is the root cause of the misfire codes. Replacing plugs and wires at that age and mileage was needed anyway and the price was very reasonable so you can feel good about things thus far. If the light returns and the P0340 comes back, you need to replace the cam sensor and syncronizer, it is in the same place as the distributor used to be on a 3.0 before they went to a distributorless ignition system in 1996. The parts are somewhere around $200 and my shop gets 1.5 hours to replace the two. There are a couple of "steps" I have eliminated over the years that save alot of time, but if it is not done properly you have to have special alignment tools needed to complete the repair. I could probably talk someone through the procedure if they were familiar with the parts.

[Northlander]

Capt. Don are you in White Bear or the North Shore this time of year?

How soon til the check engine light comes back on if thats the problem. E-mail me your thoughts on this please.

[Macgyver55]

Quote:

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Without getting too technical I can tell you there is no way on earth that the misfires could of set a cam sensor code, the cam sensor and syncronizer control fuel injector timing on that motor, not ignition.

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Actually the p0340 is in the top ten most frequent codes found. Sometimes things totally unrelated can cause codes to come up, so I'd personally never say never. Stray voltage jumping around (maybe from a bad plug wire?) can do strange things. Some Ford models, (although I haven’t found it on the Taurus) can actually exhibit a diagnostic trouble code (DTC) P0340 and/or P0344; /or P0349 due to a malfunctioning diode or open phase connection in the generator. There are quite a few Ford TSBs on this for several different models, so it’s not out of the question to be possible on the Taurus too.

We know the P0340 indicates a Camshaft Position Sensor Circuit Malfunction. The keyword here is circuit. The malfunction could be anywhere in the wiring to and from the PCM or the PCM itself. The code can be set if there is a short to ground, short to power or and open circuit. It’s probably a good idea to test the whole circuit before replacing parts, even though the odds say it is more likely the sensor if the code comes back.

I don't mean to sound like I am second guessing Capt Don since it sounds like he has shaken hands with this problem more than a few times. I'm just bouncing a few more ideas out there to keep us all thinking. Hopefully you wont see that light on for a while! Good luck!

[Northlander]

Check engine light came on right away when my wife drove it home. P0340 code came up today. Looks like Ill be out another $400 or more.

[Capt. Don*]

Mac you are right about never assuming a code is the green light for part replacement, for this leads to nothing but repeat repairs. The cam sensor circuit is actually a simple one on the 3.0 OHV. As a driveability mechanic for Ford for nearly 20 years I have had the "luxury" of dealing with the same cars on a daily basis on a wide variety of concerns. Based on this experience, and only on it and a couple specific questions of the owner did I make the decision to replace parts. These failures in the 3.0 and only the 3.0, are nothing new to me. It is a mechanical failure of the gear driven syncro that takes out the sensor accompanied by a telltale chirp at half of crankshaft speed when cold.

Parts replacing in my position is a difficult way to beat flat-rate and good way to find yourself out the door. You are right in passing along that this type of post could give people the wrong impression about the right way to make repairs, it ends up wasting alot of time and money. I did not intend this to be viewed as generic, but very,very vehicle and symptom specific. We have since discussed the vehicle off of this forum which is where it belongs at this point. I am always more than willing to lend some advice about Fords and other mechanical issues if I am able, hopefully I can save people some time and money in the process. Certain topics in which I reply, however, should be labled "don't try this at home".

[Jeremy airjer W]

That chirp drove me crazy for a couple of hours!! Once you figure it out you never forget that noise and what causes it!!!