rough idling

Hello,

This sounds like you have a vacuum leak or the throttle bore needs service here are guides to help you fix the problem

https://www.2carpros.com/articles/engine-misfires-or-runs-rough

and

https://www.2carpros.com/articles/throttle-actuator-service

and

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

Please run down these guides and report back.

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?

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?

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.

Joe

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.

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.

Joe

Only when the a/c is on - my Taurus idles rough. Turn the a/c off and it idles smoothly. No other problems

Sounds like it may be more of an engine mount issue fit runs smooth without it.Have the mounts inspected to see if they have collapsed or if they are blown out.Some Taurus models used a liquid filled mount that didnt last very well and could cause this vibration at idle. Also try cleaning out the throttle bore with carb cleaner adn a rag, this can stabilize/raise the idle a small amount and will sometimes do away with the vibration

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.

I have a 2003 Ford Taurus that at various times starts idleing rough and dies. This happens quite often and starts up again soon after. It has been put on a diagnostic machine and nothing shows up. It has happened on highways and city roads. It's like being in a death trap. Any answers?????

check fuel pressure and fuel pump is functioning correctly ?

Three days ago it started running rough during cold startup then then runs great when it warms. Has not stalled just idled rough so far.

Spark plugs are the best suspects, but ignition coils are a common cause of misfires too. When you have an engine-related problem, you need to list which engine you have. in this case there is only a 3.0L, but there is a single overhead cam and a dual overhead camshaft engine. You should be getting a "check engine light" along with a fault code indicating which cylinder is misfiring. If your engine uses the "coil-on-plug" ignition coils, swap two of them, erase the fault code, then see if a code sets for the cylinder you moved the suspect coil to.

It has been idling funny like it is misfiring. I replaced the Idle air control valve. Runs a lot better when driving. But in park it runs choppy as if it has a lope to the exhaust like if it has aftermarket cams in it. So I cleaned the TPS, MAF, and checked for vacuum leaks with throttle body cleaner. Nothing.

The only thing I can think of would be a cam shaft position sensor, crank shaft position sensor, a bad injector, or plugs. But no check engine light has came on or anything.

So no lights, no codes, what else could it be?

First eliminate all vacuum or air leaks in the system (very important)

Try cleaning the throttle body first. Remove the intake snorkel, have someone hold the throttle wide open for you and scrub the back side of the throttle plate and surrounding bore with an old tooth brush and some carburetor cleaner. Be sure to spray some into the small holes next to the throttle plate.

Hi,
my care has been idling rough when I come to a stop at a red light. it will usually go completely dead at a stop unless I put it in park. I put in some fuel treatment but this has not helped. Please let me know what you think the problem may be. Also, my check engine light is on.

Thank you,

Ashley

I would check it for tune up
check coil
check pcv valve and hose
check for a vacuum leaks
do you have check engine light on
scan for codes if so

When at first start from a cold engine, as soos as I place the shifter on drive or reverse, a rough idle occurs. When I return the shifter to neutral or park, it's smooth idle. No trouble codes. Had the trasmission oil replaced and same problem.

There are four possible sources of friction load that can contribute to under speed error or low idle concerns.
Power Steering Load
Air Conditioning Load
Electrical Load
Automatic Transmission Torque Converter Load


Most engines will have a temporary high idle at engine start up ,if not check IAC valve

Hi,

When you say a rough idle, is it a misfire or just a vibration you feel? Often times when this happens, it is the result of a worn motor or transmission mount.

Take a look through this link and let us know if anything helps.

https://www.2carpros.com/articles/vibration-noise

Since you are only feeling it when placed in gear, this could be a possibility.

Let us know.

Joe