I have a 2004 ford taurus. I recently washed the engine with a power washer. After it started idleing rough and in gear at lower rpms it would chug. I checked the code it had several misfire codes

SOURCE: Check engine light comes on. p0171 and p0351 codes found

From Lusty Kid:

I know the economy is bad, but change all of the plugs. Check your PCV Valve hose, 150 rottens them out allowing air to be sucked in, thus all kinds of codes.

Depending on mileage. Dismount the EGR valve and clean passages. If you are really good dismount the throtle position sensor body and clean out passages with Choke Cleaner., dismount where the EGR valves connects to the engine, clean out passages. Also check the hose thats behind this mounting to ensure is not clogged. If clogged clean it out. If not replace it. Is about 1.5 ft. long, connects to the PCV Valve Hose.

When is the last time you change your harness. Can't remember??? Replace it. Good Luck

SOURCE: my check engine light is on with a code of a

Did you route the new wires ezxactly as they came off the truck? There are service buletins on this issue with doge. Not sure if the same for Ford on this but check. Some plug wires if crossed will cause a P0301-P0308 code or even a P0300 which is random misfire. There may be a service buletin on this for routing and a procedure for doing so! I had to do this on my dodge with the 5.2 ltr. The guy i bought the truck from gave up and i got it cheap this fixed the problem!

SOURCE: My 2004 Taurus has a rough idle. Plugs, wires,

i have the same issue.....i actually have a cylinder that is dead and causing this to occur...... the only fix for me is a new engine......good luck

SOURCE: 1999 Ford Taurus 3.0L V6 24V DOHC Duratec Engine

i would check the plug wires and the coils you check the plug wires for bad spots at night start the motor up and look at the plugs if you see a spark arch out the wire and to a peace of metal then the plug wires need to be replace.

Jeffrey Turcotte

• 8991 Answers
• Posted on May 20, 2011

SOURCE: i have a 2004 ford freestar 3.9 The engine light

Hi, the first step I recommend is to check for spark. You can do this by starting the car and then carefully pulling up the boot to the #1 ignition wire at the coil. If sparks are jumping inside the boot, you have spark and the ignition system is working.

1. Ignition: If there is no spark, shut of the engine and use an ohmmeter to check the impedance of the coil. Take the boot off, and connect your ohmmeter from the coil terminal to the engine ground. The resistance should be around 10-20 kohms. If not, replace the coil. If yes, the problem is the ignition module under the coil.

Now, assuming you have spark (which I believe you do, because the coil runs 2 cylinders, and you only have one cylinder that is misfiring), the problem will be a lack of compression or a bad injector (or possibly the injector wiring).

Note: I will provide repair steps once the troubleshooting is complete and the problem identified.
Also, if you do not have a multimeter, you can get one for $10-20 at radio shack or even Walmart. It will save you money overall--or maybe you have a friend that you could borrow a meter from.

2. Injector: The next easiest test to run is to see if the injector solenoid is clicking. You can do this by holding a long screwdriver to the injector and hold the other end of the screwdriver to your ear. With the engine running, you should hear the injector clicking. If not, you have a bad injector or a wiring problem. To determine whether the problem is the injector or the wiring, pull the connector off the injector and measure the AC voltage in the connector with the engine running. The voltage should be 1-2 volts or similar to that voltage of any other injector connector.
If the voltage is good, but the injector is not clicking, replace the injector.

3. Valves/compression: the last possible reason for a misfire is a lack of compression. The intake valve must open to accept a fuel/air charge, and both valves must be closed for the cylinder to fire. Sometimes an exhaust valve will burn and not hold compression. A blown head gasket can also cause this problem. The test we use to check the valves is a compression test. You can borrow or purchase a compression tester if you get to this point. Remove a few of the spark plugs including the cylinder that is misfiring. Screw the compression tester into the spark plug hole and crank the engine for a few revolutions. Record the pressure on the gauge, release the pressure, and go on to the next cylinder. If the pressure is much lower on any cylinder as compared to the highest cylinder, the cylinder head will have to be removed to correct the issue.

Please let me know the results of your troubleshooting and feel free to ask questions as you go.