Asked by starrider99 Apr 10, 2009 at 07:01 AM about the 2000 Ford Taurus SE

Question type: Maintenance & Repair

This is my first post on this site so let me know if I am asking too much at once or any other issues my post may have. OK so I just bought a 2000 Taurus SE with a 6 cylinder 24 valve DOHC motor. I knew it had issues. My code reader tells me P0304 is the reason it is running bad. It's been a while since I have turned a wrench so my learning curve is straight up.I tried a few basic things like swapping the plugs and the coil pack on top and the boot from number 5, which had no effect. Which was a good thing since I found that the #5 plug was loose and the boot was all carbonated up? Oddly enough the #4 plug looked like it had carbon build up due to not firing even though my tests indicated it is getting spark. I only have a Haynes manual from VIP so I may refer to an item incorrectly until I get actual shop manuals. I also put in high test and ran a bottle of fuel system cleaner and a bottle of injector cleaner.I held the gas to 3k rpms while in park the light went out. As soon as I let up it came back on. I replaced the fuel filter and front 3 plugs just as a quick try. Still ng. When I get it rolling the light goes out. I can actually feel it get better some times. I wil be doing 30 or 40 and feel it get a boost and then the light goes out. If i come to a stop it is back on. Start drive at at least 1500 to 2000 rpms and the light goes out. Today I pulled the mainfold to change the plugs and swap the injectors to see if it fixes or changes the code. No Change. In the process I soaked the throttle body and all the other intake parts with carb cleaner. I must say it looks good runs like crap.I replaced all o-rings on the injectors and swapped them around just in case the #4 was bad since the code is P0304. I replaced the air filter.I also had to replace the coolant hose that is closest to the air box since in the process of replacing the PCV I broke off the little piece that sticks up. I swapped around the coils. Took it to a shop to get a sticker and they called saying it was running so rough they couldn't even do any further testing to pass inspection. They said number 4 had 40lbs of compression. I pulled the valve cover and as far as I can tell with it running or not the valves seem to be working. No broken springs or obvious issues. Now my low coolant light is on. can this be due to the fact I only put water back in just in case I had to drain it again? Or could i have messed up a wire to a sensor? I think there are at least one or two in that area of the PCV that I replaced. I haven't been able to get my own compression tester yet but that is my next plan to verify what they said. If it is correct and the valves seem to be moving should I shoot some oil in the plug hole and do a dead crank test to see if it comes up? Thanks for any and all help.

1 Answer

Mike Tritle

Well, you've certainly covered the ignition and fuel system through a somewhat unscientific scientific method. With the 40 psi compression reading in #4 I'm thinking and afraid you're headed in the direction of the dreaded burned exhaust valve. I doubt you have a broken ring or ventilated piston because the problem comes and goes with rpm. The best way to determine the mechanical seal of the cylinder is with a leak down test. This involves connecting a tester with two pressure gauges that will monitor both input pressure to the remaining pressure in the cylinder. A good one at operating temp will have less than a 10% difference in the readings max. Example would be input 100psi should yield no less than 90 psi on the secondary gauge. You can do similar with a compression tester dry then wet. If there's no change cylinder is good. Slight increase wet over dry, worn rings. Low initial reading with little or no change wet, burned valves. Good luck and keep us posted!

Your Answer

Add photo

Related Questions

  • now it wont start at all. I am fixing to burn it to the groud 4 answers

    refer to earlier question of 5 days ago, multiple codes p174 p304 and p1744, misfiring hard to start now wont start at all someone must have something to say to help or not. I am fixing to burn it to ...

    1999 Ford Taurus SE


    Maintenance & Repair

  • I have a 2008 Ford Fusion SEL with the 3.0L. What could be causing codes P0300, P0304, P0305, P0306 and P2197. 2 answers

    I have a 2008 Ford Fusion SEL with the 3.0L (118K miles). What could be causing codes P0300, P0304, P0305, P0306 and P2197. The car shakes and rattles while running. These issues happened suddenly ...

    2008 Ford Fusion SEL V6


    Maintenance & Repair

  • p0304-misfire-can't get rid of the code- 2 answers

    i've tried plugs, wires,coils and had other areas tested by trusted mechanic

    1997 Ford Escort


    Maintenance & Repair

  • Trouble shoot codes p0113, p0171, p0174, and p0304 1 answer

    I need to know where is the IAT sensor located on my vehicle. Also I just replaces the fuel pump and filter and also the power steering pump. But codes coming up say System to Lean Bank 1 and on...

    2001 Ford F-150 XL LB


    Maintenance & Repair

  • Engine light on please help? 6 answers

    I have a 2006 Ford (Exploder) Explorer Eddie Bauer, and I have taken to the mechanic and the code reading at first was P0303. They could not figure out what else was wrong even after they changed sp...

    2006 Ford Explorer Eddie Bauer V6


    Maintenance & Repair

Search Ford Taurus Questions

Ford Taurus Experts

#1 Tom Demyan
Tom Demyan
Reputation 2,280
#2 lightGear
Reputation 1,390
#3 spock8113
Reputation 1,230
View All

Related Models For Sale

Used Chevrolet Impala"
1,443 Great Deals out of 45,353 listings starting at $170
Used Ford Explorer"
1,073 Great Deals out of 46,495 listings starting at $850
Used Ford Mustang"
653 Great Deals out of 42,120 listings starting at $1,500
Used Ford F-150"
3,096 Great Deals out of 178,823 listings starting at $1,450
Used Toyota Camry"
1,181 Great Deals out of 84,988 listings starting at $1,517
Used Honda Accord"
891 Great Deals out of 73,570 listings starting at $1,000
Used Chevrolet Malibu"
1,064 Great Deals out of 56,821 listings starting at $1,500
Used Nissan Maxima"
364 Great Deals out of 23,302 listings starting at $999
Used Ford Focus"
1,134 Great Deals out of 72,374 listings starting at $1,300
Used Nissan Altima"
1,086 Great Deals out of 80,598 listings starting at $1,500

Used Cars For Sale

2015 Ford Taurus SE For Sale
270 listings starting at $15,950
2014 Ford Taurus SE For Sale
138 listings starting at $12,393
2013 Ford Taurus SE For Sale
193 listings starting at $10,574
2012 Ford Taurus SE For Sale
7 Great Deals out of 76 listings starting at $9,690