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Hopefully I've posted this in the correct area., this is the first time I have used any forum to repair a vehicle.

I have a 2000 Taurus SEL 3.0 Duratec 24V. 94,XXX .miles. It has a rough idle, check engine light, occasionally the check engine light will blink (while blinking it seems as though there is no kick down acceleration and if I put my foot down on the pedal it accelerates slowly). This is ONLY a problem at idle except for slow acceleration when the check engine blinks. The idle does become more rough when the A/C is on. Rough idle is not affected by clearing the codes out of the ECM. I have only pulled codes once as I do not have a code scanner. I cannot remember the specific code other than BANK #1 Lean.

I have read multiple posts about a rough idle on a duratec, a vacuum leak is usually blamed I do not believe I have that problem. The last owner had a mechanic say it was potentially a "burned valve" but he also never looked at the vehicle or had near as many details as I have. This cannot be that difficult or expensive to repair since it's only an at idle problem.

I replaced the fuel filter, spark plugs, the old plugs did not appear to be worn, fouled, or defective. replaced the upper intake gaskets, ran Amsoil PCI fuel cleaner additive, and replaced the PCV. I noticed that the intake had a light buildup of engine oil. My guess is oil buildup has been corrected by replacing the PCVs. I cleaned the throttle body with approved cleaner and a toothbrush, along with spraying clean the IAC valve, EGR valve, and MAF sensor all with the appropriate cleaners. Inspected the Coil Over Plug coils and boots and there appears to be no cracks or carbon traces of a misfire.
It also does not appear to have any issues with the cat converters although the muffler does seem louder than normal (I'd guess due to the rough idle)

This all leads me to believe I have a sensor issue. If I remember correctly the O2 sensor readings are not taken into account for the first few minutes of operation until the vehicle has warmed up and I have had the blinking light with poor acceleration happen within 30 seconds of startup. I'm out of options on repairing this issue since I do not have a scanner and I cannot afford to replace various sensors until I find the right one.

System too lean would tell me either too much air, or not enough fuel so I do not believe that this is an ignition problem. I have ruled out a vacuum leak after inspection of all hoses and using throttle body cleaner sprayed over the manifold and hoses.

The previous owner of the car sold me the car with the rough idle condition, he also gave it a tune up and tried to diagnose the problem but he did not look deeper into the problem His 18yr old daughter did not feel comfortable with it's rough idle....apparently a fully loaded SEL model, leather seats, mach stereo, moonroof, heated rearview mirrors and polished rims, and immaculate condition. Some kids are just too spoiled. She wanted a grand prix, I'd pick a newer ford over a pontiac any day I'm very proud of Fords quality improvements over the years and disappointed in chrysler and GM products.


I'm sure there's more information I can add to my diagnosis of this car but LOL, if no one replies to my post I'm just talking to myself.

Please help me with this issue as it is causing me to lose sleep thinking about it as I'm sure many mechanics do.
 

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You seem to have eliminated all the usual suspects in trying to cure the rough idle . Only thing I can suggest would be the engine coolant temp sensor which lets the ECU know how much fuel to supply .I also suspect a vacuum leak but you say you have checked that out . Another quick test on the alternator output at idle with air con on would rule something else out . If it was a burnt valve it would show on a compression test . Best I can think of just now to suggest checking . I can understand the previous owners daughter not feeling comfortable with the rough idle and I wouldn't let my daughter run a car with that problem but as you say , it's must be a hard life for someone of that age to drive a car as good as that ! You got to remember though that we all treat our daughters that way and are easily manipulated by them !
 

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I just had the same problem,2001 Taurus. I replaced the coil pack and my car runs like its brand new.

Hopefully I've posted this in the correct area., this is the first time I have used any forum to repair a vehicle.

I have a 2000 Taurus SEL 3.0 Duratec 24V. 94,XXX .miles. It has a rough idle, check engine light, occasionally the check engine light will blink (while blinking it seems as though there is no kick down acceleration and if I put my foot down on the pedal it accelerates slowly). This is ONLY a problem at idle except for slow acceleration when the check engine blinks. The idle does become more rough when the A/C is on. Rough idle is not affected by clearing the codes out of the ECM. I have only pulled codes once as I do not have a code scanner. I cannot remember the specific code other than BANK #1 Lean.

I have read multiple posts about a rough idle on a duratec, a vacuum leak is usually blamed I do not believe I have that problem. The last owner had a mechanic say it was potentially a "burned valve" but he also never looked at the vehicle or had near as many details as I have. This cannot be that difficult or expensive to repair since it's only an at idle problem.

I replaced the fuel filter, spark plugs, the old plugs did not appear to be worn, fouled, or defective. replaced the upper intake gaskets, ran Amsoil PCI fuel cleaner additive, and replaced the PCV. I noticed that the intake had a light buildup of engine oil. My guess is oil buildup has been corrected by replacing the PCVs. I cleaned the throttle body with approved cleaner and a toothbrush, along with spraying clean the IAC valve, EGR valve, and MAF sensor all with the appropriate cleaners. Inspected the Coil Over Plug coils and boots and there appears to be no cracks or carbon traces of a misfire.
It also does not appear to have any issues with the cat converters although the muffler does seem louder than normal (I'd guess due to the rough idle)

This all leads me to believe I have a sensor issue. If I remember correctly the O2 sensor readings are not taken into account for the first few minutes of operation until the vehicle has warmed up and I have had the blinking light with poor acceleration happen within 30 seconds of startup. I'm out of options on repairing this issue since I do not have a scanner and I cannot afford to replace various sensors until I find the right one.

System too lean would tell me either too much air, or not enough fuel so I do not believe that this is an ignition problem. I have ruled out a vacuum leak after inspection of all hoses and using throttle body cleaner sprayed over the manifold and hoses.

The previous owner of the car sold me the car with the rough idle condition, he also gave it a tune up and tried to diagnose the problem but he did not look deeper into the problem His 18yr old daughter did not feel comfortable with it's rough idle....apparently a fully loaded SEL model, leather seats, mach stereo, moonroof, heated rearview mirrors and polished rims, and immaculate condition. Some kids are just too spoiled. She wanted a grand prix, I'd pick a newer ford over a pontiac any day I'm very proud of Fords quality improvements over the years and disappointed in chrysler and GM products.


I'm sure there's more information I can add to my diagnosis of this car but LOL, if no one replies to my post I'm just talking to myself.

Please help me with this issue as it is causing me to lose sleep thinking about it as I'm sure many mechanics do.
 

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Discussion Starter #5
Thank you to everyone that has replied so far. I didn't think of the engine coolant sensor, the inside temp reading appears to be normal and doesn't fluctuate while driving. Does the temp sensor send different information to the ECM than it does to the dashboard gage? Also the rough iddle is present no matter what the temperature of the motor. Idles rough when cold, and when warmed up.


I believe the 2001 model taurus has a single coil pack rather than 6 individual coils directly over the plugs. I've done the test where I've sprayed water over them while in a dark garage and I have no seen any sparks arching. I suppose it would not be difficult to purchase. ONE coil and replace one by one each coil on all 6 cylinders to see if the idle changes. I plan on going and having the codes pulled again today afterwards I will clear them out again.

If anything I would like to RULE OUT various sensors and conditions that could cause this rough idle. I'd love to rule out the expensive ones, lol. I'm trying to remember back to vocational school when they said what sensors ARE taken into account at first start up before the engine has warmed up. Anyways, I plan on having the trouble codes posted on this forum later tonight. Thank you for your feedback so far and any other help is greatly appreciated!

Gotta love Ford. GM and Chrysler begged for bailout money when Ford asks "Does anyone need a loan? We've got money to spare".
 

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Discussion Starter #6
The trouble codes are :
P0174- Bank 1 too lean
P0171- Bank 2 too lean
P0304- Misfire cylinder #4

I take it that the ignition coil over plug #4 could be defective. If there is a way to test the coil with a voltmeter I would prefer to test rather than "parts change" it out to see if the issue has stopped. How would lack of spark cause a lean condition? Wouldn't unburned fuel cause a rich condition? LOL I wouldn't ask so many questions if I just had the 65 dollars to buy a coil and roll the dice to see if I got lucky and fixed it.
 

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The coils are usually the problem. You could switch it with another cylinder and see if the misfire moves with it.

I wouldn't worry about the other codes until the misfire is fixed. The hose to the PCV is often leaking causing a lean condition and often those codes.
 

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Discussion Starter #8
I hope me adding this to the thread reposts this again so someone can reply. I'm still having the above issue. I've checked for vacuum leaks and I cannot find any with throttle body cleaner being sprayed on the engine. I have moved the #4 coil with other ones and the misfire does not move with the coils. Before I thought I had a crack in a coil but it ended up being just a scratch. I made sure by looking in the dark, and by placing insulation around the coil. The rough idle issue tends to be worse in warmer temperatures. I can still disconnect the battery and it will run fault free, and smoothly for a day or two. I'm about t replace the PVC valve and I'll check the hose going to it as I hear it's popular to collapse. I'm doubt this is the issue, it's not leaking air, and the hose is around a year old. I'm convinced that the oil film in the intake is being pushed back to the fartest cylinder (#4) and causing the misfire. My guess is the PCV is letting too much oil into the intake. The car still accellerates just fine, and so long as the check engine light isn't blinking, it runs just fine other than a rough idle. I believe the last owners replaced the muffler due to the miss causing A less than smooth airflow through the exhaust. If anyone else has any solutions or tests I'm looking forward to hearing them.
 

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Discussion Starter #10
I've changed the upper intake gaskets twice. Each time the same cylinder has a misfire. Hell I'm sitting in it right now and it's running just fine after I reset the battery. Since it's hot this time of year the check engine light will turn on and back off a few times until finally it comes on and stays on
 

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I'm going to have to say that I haven't changed any bolt seals. I've only changed the little rings that go inside the gooves of the intake that expand each time I remove the intake so I'm forced to buy another set. I'm still doubting that there's any gasket issues with the intake. As I said I've taken cleaner and sprayed everywhere around the motor and there is no change in the idle. The PCV tube itself has been replaced by the previous owner who was trying to fix the same rough idle issue. I didn't see a reciept for the PCV valve itself so I'm going to change that out once I have a few more ideas of what might be causing the issue. I've read a few posts on people that say that having some oil inside the intake is normal. I don't see it as being normal when there's as much as there is. It's not blowing back into the air filter so I don't think it's a major problem with the lower half of the motor. I haven't pulled the trouble codes in quite some time so I reset it tonight and I should have the chance to remove the upper intake again. Fron what I've read, I shouldn't have to get too deep into the top end so long as I'm able to get a small pair of pliers that's good enough to take the PCV out without having to take apart much. I still can't get around the fact that when I first posted in this forum I removed the coil on #4. The bank closest to you from the front of the vehicle, far passenger side. I'm still stuck on oil that could be "flowing" down the upper intake and then making it's way down into the farthest cylinder. Ugh, I also have a 95 ford ranger that's having a cranks with no start unless youlet it set 10-40 mins. If u go back it'll start up no problem. I'm thinking the EGR is stuck upen and it's trying to start cold on a warm motor letting too much hot air into the engine making it run on what seems like half it's cylinders. I'm more concerned about this damned Taurus. Under acceleration it runs perfectly, take it on the highway and it'll launch with no passing power issues. (Unless the check engine light is blinking).
 

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Discussion Starter #17
I haven't checked the codes in a few months but when I had moved the coils back then, the misfire stayed on cylinder #4. The misfire would only present itself after running poorly for quite some time. At first I didn't have a misfire code at all. I take it the link you've shown me is saying to clean the MAF and replace the PCV tube. I don't have a new tube so I won't be able to work on it until I order the part from ford. I do know for sure that tube was replaced a little over a year ago. I'm not sure of the fuel trim relearn process and I do not have a scanner to read detailed engine information so I'm not able to tell volates wattages, and fluz capicitor storage capacity, lol. The MAF is the part that comes right off the air cleaner with the wire mesh and a little sensor inside right? I'll have to get the cleaner for it I'm sure. I appreciate your help so far so thank you
 

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If it ran the same with it unplugged, it should be okay. When they run better unplugged, then the MAF is either dirty or defective. That link mentions the lower seals.
 

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I have a DOHC 1998 sable with this exact same problem and the codes that are poping up are something 171 and 174 I believe it said Engine banks 1 and 2 running lean. I heard it could be alot of things i was thinking maybe my hoses have started cracking to much.
 
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