Rough idle at start up

Here's a guide to read, it may help you figure it out

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

Sounds like it could be an injector bleeding down over night, or even a very minor issue with ahead gasket putting water in the cylinder overnight.

Definitely start basic.. be sure the tune up is good, they run rich when cold and border line wires/plugs can misfire in this condition.

Do you notice any coolant loss?

You should scan for codes even if there is no check engine light... you can look at misfire history to see what cylinder it is and go from there

These cars are notorious for developing a leak in the pcv hose at the intake and cause rough idle even stalling. When the hose gets warm from the motor running the hose softens enough to stop the leak slightly and then runs fine.Check this hose right at the intake and see if there is cracks or small rip at the elbow of the hose

Hi, I hope you can help, I am stumped. Used fuel tank recently installed, now have to trickle fuel in.Was told the check valve was plugged, garage said they blew it out, but still can't add fuel to tank without clicking off 1000 times.
Rough idle under load. runs fine at highway speeds, no hesitations, no misses, plenty of power, but pull up to stop sign and feels like its about to stall. I replaced plugs, wires, coil pack, fuel and air filter. Pulled fron injectors,and cleaned them.Compression test on front 3 cylinders #4 125 #5 150 #6 160. Oil level normal not milky, anti freeze level normal. Don't hear any vacuum leaks. Car sat for 4-5 months. Could it just be junk from the used tank ? I've tried running techron in the tank, and added 1/2 quart marvel mystery oil to help clean top side. Any thoughts would be greatly appreciated

Check your EGR valve and EVAP solenoid

The egr valve appears to be working. The scanner only threw a code for the fuel gauge sending unit (which also isn't working). Is the evap solenoid under the trunk having to do with vapors from tank?

Thanks

Yes it does. It is responsible for purging the vapor in the system to be burned while the engine is running. If the system is full of fuel vapor (fumes) - the tank has high pressure and no more fuel can enter. Have the solenoid checked out.

Will do thank you. Would a bad evap solonoid also cause a rough idle ?

Yes it will, but not as much as bad EGR will cause.

The engine idles rough and the exhaust is rich with gas. As soon as you hit the accelerator, the problem clears up and the gas milage is the same. As of now, no problem codes have popped up and the "Service Engine Light" has not come on. The engine bounces between 500 and a 1000 rpms. Starts with no problems. I am not sure if its my imagination or not, but it seems that if your going 55 MPH down the road and you let off the accelerator, the engine doesn't slow down until you hit the brakes. What's your thoughts?

May be the idle air control...mounted on the side of the throttlebody, remove and clean the carbon out. Or replace it...Also you may have a vacuum leak, get a can of spray gumout, spray the vac lines and maniflod area, when the idle changes, youve found the leak! You want the engine running and spray on the outside but do direct the stream onto the hoses, if it is a vacuum leak, the engine idle will change speed, then you have detected a leak, repair the vacuum leak and see how it runs!

Hi. This car suddenly has no power climbing hills, and shifts down to lower gears to keep going. Plugs look ok, were cleaned and regapped and replaced. Checked and topped all fluids, added octane booster and filled up w/ hightest gas. No obvious sound for compression leak. Several months ago I replaced the plugs as the three on the front of the transverse engine had the anodes burned clear off while the rear plugs were fouled and hardlly used. I also replaced the voltage distributor pack ?? mounted on the block, which fixed thihngs for five months. No water iin the oil. Car starts ok, but idles and runs roughly. plug wires look ok. High pitched sound low passenger side may be a failing water pump, but no leaks seen. Any ideas!! pw

Check the ignition timing/fuel pressure/exhaust for restriction and also the TPS/MAF/MAP sensors-

Was driving slowly through residential area, car started acting like it wanted to stall. After increasing speed it stopped doing that. Next day engine light came on and it occassionally will idle roughly when sitting at a stop light or driving very slowly. I am a single woman and don't want to get jerked around at the dealership so can you give me an idea of what could be wrong before I go in there? How do you check codes in a car? There use to be a way on turning the ignition three times and a light would flash several times for whatever code was wrong.

take your car to autozone and have them scan the car for codes. they do it for free. get back to us with the codes. you most likely just need a tune up. if you get a code po 300-306 then for sure you need a tune up. get back to us

I went to Auto Zone and they hooked up a small device and told me my car was running "lean" I tried to question the young man but he told me it could be several different sensors and that I should take it to the shop. I asked if it could mean it needs a tune up and he said it could but I shouldn't try anything until I took it to the shop and got official codes.

ok this is probably going to be alot easier that a tune up. these engines get vacuum leaks and run lean because the pcv valve vacuum hose gets deteriorated and leaks causing your symptom. this is a very easy and inexpensive repair.

YOU ARE AWESOME!! We looked at the PCV hose and found cracks in the elbow. Once that was fixed all was good. Thank-you so much. This could have easily caused me money I didn't have if I had to take it to the dealer. Thank-you again!!

I am having the same issue as this lady but I cannot find any place to purchase the rubber hose or the 90 degree rubber hose part. Can someone please direct me to a place online?

Thanks.

2002 Taurus engine runs rough at idle for first 30 seconds and then smoothes out. Using scan tool the only thing unusual is the ignition advance is only 2 to 3 degrees and then moves up to 10 to 12 degrees as engine smoothes out. What things control the timing?
Thanks. Lee

go to any parts store and purchase 1 foor of 3/8 rubber fuel line and make a real wide bend. who cares if it looks goofy, it will work.

The computer controls the timing based on crank and cam sensors. Have you checked for simple things like vacuum leaks? Has the check engine light come on with any codes?

Get codes P0301 and P0316 once in a while. I have replaced injector #1, changed plugs, checked for vacuum leaks, cleaned mass air sensor, checked: coil, fuel pressure, intake air temp, coolant temp and egr valve. Nothing has changed.
Thanks, Lee

Lee:
Have you ever checked compression in that cylinder? When steel heats, it expands. I wonder if you have a low compression problem only when cold. I know that is a stretch, but the only other thing is the PCM. If you have replaced plugs, injector, fuel pressure is good, and the injector is working properly, it has to be one or the other. One last thought, have you checked the temp sensor?

Still have same problem. Why would the timing ever be set down to 3 degrees for about 20 seconds after starting.There must be some signal that is causing this.
Thanks, Lee

hi the other day i took my daughter to the post office
on returning home i pulled up to a stoplight and my 2000 taurus started idleing rough i thought the car would die on me at the intersection but it didnt so when the light turned green i took off like always. it runs fine when driving but only when i stop like at a stoplight
the car again starst idleing rough again when i take off it's fine i cleaned the maf with maf cleaner i hope that would help but it did not. there is also no check engine lights on the car has always ran fine until now. thanks any reply will be aprecieated thanks

I call that preventive maintenance. you did the right thing to clean the maf sensor because it is one of the sensor is most likely to cause that problem.
beside that you have the IAC sensor and wiring.
the IAC is a kind of small nose for the engine to breath when the gas pedal is not pushed down, same as saying when coming to a stop.if that is malfunctioning, the car will feel like choking when idling.
In real life, we said"everybody is inocent until proven guilty" :-)
there is no code(s) right now, the car is driving fine so far.
let me know as soon as possible there is other symptoms or engine light, so we can take care of it.

When engine is first started the Ignition advance is 10,it then goes to 12 deg and the rpm is 1508,3/4 second later it goes to 8 deg and the rpm is 1609, 3/4 seconds later it is 5.5 deg and rpm is 1236, 3/4 seconds later it is 4 deg and rpm 1274, 3/4 seconds later it is 3 deg and rpm 1436, 3/4 seconds later it is 3 deg and rpm 1231, it stays at 3 deg for about 17 seconds and the rpm slowly moves down to around 900. The timing then goes to 6 deg, 3/4 seconds later 7.5 deg, 3/4 seconds later 9 deg, 3/4 seconds later 10.5 deg.
All the time during the timing being at 3 deg the engine runs rough. As soon as the timing gets back up above 10 deg it runs smooth and doesn't miss if you put it in drive.
All sensors are working according to the monitor.
Any help would be appreciated.
Thanks, Lee Jackson

what do i use to clean the iac sensor with. can i use the same can of maf cleaner i have or does it require a diffrent cleaner. i will give it a good cleaning and see where it gets me thanks for your prompt reply for the first question.

Without being there this is a tough one. The PCM adjust ignition timing. If everything is working properly, that is my guess.

it is attached to the throttle body

and look like this ,here seen in different positions

When suspecting a IAC problems ,first perform a visual inspection.most problem can be found in wiring harnesses, conectors(oily or corroded connectors). an unstable idle or stalling can be cause by vacuum leak or faulty PCV valve.in some cases just dirty electrical connections at the IAC can cause a problem. ***The IAC Valve Assembly is NOT ADJUSTABLE and CANNOT BE CLEANED If physical evidence of contamination exists, install a new IAC valve. Testing: Key symptom is elevated idle speed while noise is occurring. "Snapping" the throttle can induce the noise. While the noise is occurring, place an EngineEAR probe near the IAC valve , If the IAC valve is making the noise, install a new IAC removal:

if the vehicle still stall after testing or replacing the IAC, nest move will be to test the computer ground. let me know .

Also, about 4 seconds after the timing goes down to 3 deg, the fuel sys1 goes from open loop to closed loop.
Don't know if that helps any!
Thanks, Lee Jackson

I have a 2000 taurus doing the same thing. I changed the MAF sensor and the IAC valve and the problem is still there. Just a heads up not to waste the money.

Could bad information from the knock sensor cause the timing to be set down to 3 deg for a short period of time? Is there any way to check or bypass the knock sensor?
Thanks again, Lee Jackson

Yes, the knock sensor os designed to adjust the ignition timing to its most efficient point. If it is bad, it could cause the timing to be adjusted incorrectly.

My girlfriends car (2000 Ford Taurus DOHC) had a similar sounding issue. It ended up being the lower plenum intake manifold gaskets. An easy way to check to see if this is the problem is to spray brake cleaner along the interface between the lower plenum and cylinder head (would also work by spraying brake cleaner between upper and lower plenum if the leak is in that region). The idle should pick up momentarily right after spraying the brake cleaner. The idle will go rough again after a second or two. However, if it reacts to this then odds are it's the intake gaskets. You can get a full set of intake gaskets for around $15 bucks at most auto parts stores.

The repair isn't too complicated and can be performed by a novice/average mechanic in around an hour and a half if great care is taken. Ensure to not get ANYTHING in the intake ports once the intake manifold is off.

Hope this helps someone.

Engine Performance problem
1999 Ford Taurus Front Wheel Drive Automatic
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my 99 taurus, 3.0L, entech DOHC, developed a rough idle, service engine light is on.

Low mileage (88,900), very clean, nothing obvious wrong.

Any diagnostic suggestions appreciated.

UPDATE:
Had the controller scanned and have 2 codes;
P0171 System too lean (Bank 1)
P0174 System too lean (Bank 2)

Air leak? Gasket? Vacuum leak? Dirty throttle body?

Ideas on where to go from here much appreciated!

Start at the beginning and find the codes in the pcm and we can go from there.

I disconnected the knock sensor and nothing changed! Any other ideas?
Thanks, Lee Jackson

first thing to do is check yoru fuel pressure and scan for codes, start there. then take your maf cleaner and clean teh throttle plate on both sides as they get gunked up with oil and cause similar problems. then check for any vacuum hoses off or any hoses/valve cover connectors that are rubber for holes. also there is tube that runs from the intake to the egr connectins that tends to get loose,you can either get anew part or try putting a zip tie on it and tightening itup, it wil last for a little while.

I have a 1999 Ford Taurus that is having the same problem. Did you ever get an answer as to why this is happening and how to fix it?
Thanks.
Mike


[quote:c553e85dd8="99tauri"]Engine Performance problem7
1999 Ford Taurus Front Wheel Drive Automatic
----------------------------------------------------------------
my 99 taurus, 3.0L, entech DOHC, developed a rough idle, service engine light is on.

Low mileage (88,900), very clean, nothing obvious wrong.

Any diagnostic suggestions appreciated.

UPDATE:
Had the controller scanned and have 2 codes;
P0171 System too lean (Bank 1)
P0174 System too lean (Bank 2)

Air leak? Gasket? Vacuum leak? Dirty throttle body?

Ideas on where to go from here much appreciated![/quote:c553e85dd8]