2003 Ford Taurus

Engine Performance problem
2003 Ford Taurus 6 cyl Two Wheel Drive Automatic 113000 miles

I have a 2003 Ford Taurus SES, 3.0L Duratec DOHC. It's running really rough. Started out just a slight hesitation upon accelerating, in less than a week, it began to miss. Replaced plugs, wires, coil pack, didn't fix the issue. It idles really hard and occasionally makes a loud popping noise like a backfire noise, under the hood. There's also a slight hissing noise, so I was thinking maybe a vacuum leak, but I can't find one. Took the IAC off, checked it out and cleaned it, put it back on the car and still had the same problem. I've thought, PCV, EGR, MAF. But I have no idea. If anyone has had similar problems and figured it out, PLEASE let me know.

Also, it's been running like this for a couple of months, but recently got so bad we had to park it. The problem with diagnosing this issue is that the check engine light has only appeared intermittently and doesn't stay on long. Took it to O'Reillys and had them check it and the codes it threw were po300, po301 and po316.

. Fast forward a bit.I've now replaced the PCV Valve and it seems to be running much more smoothly. BUT, now I hear an exhaust noise I didn't hear before. Out of the tailpipe comes a noise that sort of sounds like a muffled outboard motor. Recreating the noise via text, the closest I can come is " blub blub blub blub blub". Could this be the catalytic converter?
July 25, 2009.

P0300 random misfire
p0301 random misfire cylender 1
p0316 engine misfire detected on start-up(first 1000 revolutions)

If you already replaced the plugs, wires, coils. There has to either be a major vacuum leak, low compression (I would check cyl 1), a problem with fuel pressure, and the catylatic converter for being plugged.

If you hear a hissing, there has to be a vacuum leak. Check power brake booster, intake.

Let me know what you find.

Replaced the pcv valve and it is idling way better. I do believe there may've been a vacuum hose that was loose, but as we took the whole dang car apart to get to the pcv valve, when we put everything back on, we made sure all the hoses were snug.

Now we have a problem we didn't notice before, obviously because it was making so much noise while idling. An exhaust noise. While standing at the rear by the tailpipe we hear a " blub blub blub blub". Could this be the catalytic converter?

Jul 25, 2009.
I doubt it's the converter. It is closer to the front of the car. Chances are the muffler has a small rust hole or there is one in the tail pipe.

Let me know what you find.


Okay, replaced the camshaft sensor now, as that was one of the codes it had thrown in the past. Car still runs like a pile of crap. What a shocker. Anyway, upon looking down below the left side of the engine (which would be in the back under the hood, since the front of the engine is on the passenger side.) We can see that the exhaust manifold is glowing bright red after the car runs for about 5 minutes. Now we're certain this catalytic converter needs replaced, but we fear that this is a symptom of something else that we haven't been able to diagnose and repair.
Any suggestions? Getting the cats replaced is going to be big money, I sure don't wanna get it done, then turn around and have to do it again after we finally figure out what's wrong with it (other than it's a taurus. Sorry, just not a fan of Taurus'. Wonder why?)
I would put a video of what it's doing, but I don't think I can on this site. Perhaps upload one to Youtube.I'll post link here if I do.

Aug 1, 2009.
If it's glowing red, it's plugged. If you want to be certain, you could check back pressure before and after the cat. There is a special too to do it.

Don't feel bad, I own a Ford too. It has been a great car until gas prices went up and I couldn't afford to drive it. So, I got a little Chrysler Cirrus, parked the Ford (11 MPG), and as a result, everything rusted under it. Brake lines, rad support, body mounts. For me to fix it myself I'm looking at over a grand. To top it off, my wife, who the Ford was purchased for, now would rather drive the Cirrus so I'm stuck with a vehicle, making payments on it, insurance, and have to fix it to park it again. One can not get ahead in life.

Let me know if you have other questions. Also, thanks for using 2carpros. Com.


Valve seats. Common issue on these motors. Do a compression/ leak down test to confrim. Just repaired another one of these this week. Good luck.

Oct 26, 2012.