With the Ford Taurus I've worked on the general issue has always been, especially with the age of your vehicle, the Exhaust Gas Recirculation (EGR) system and Positive Crankcase Ventilation (PCV) valves. Also there could be some more issues I would go through:
1) Possible bad engine mounts?
2)Possible misfire condition, that does not throw an OBD code, Does the engine shake in drive and reverse? Look at it with the hood open and double check it in drive with the e-brake on and someone in the car just in case
3)Also the Vulcan and Duratec V6s are very picky about spark plugs and such so are you sure they are properly gapped and make of spark plugs?
I would check all the intake components first as usually these fail on the Taurus:
http://www.amazon.com/Standard-Motor-Pro...
http://www.amazon.com/Standard-Ignition-...
Also I would recommend a new air filter and idle air control valve, mass air flow and throttle body cleaning.
Many TAURUS engine do NOT have EGR VALVES! My 1990 wagon did NOT have one, but you will do yourself a BIG favor by following my advice to the LETTER! FIRST< take $20-30 to ANY oil change place and have the IDLE AIR CONTROL VALVE removed and cleaned! I use ONLY AMSOIL POWER FOAM for this job! Then have them clean the THROTTLE BODY and run AMSOIL and GUMOUT through your PCV valve! The FORD 3.0 is one of the BEST engines to be found ANYWHERE! IT will last EASILY to 350k miles! GET A MILD motor flush and NEVER EVER use VALVOLINE in it again! Use ONLY MOBIL ONE 0W-30 oil! If you WANT to waste fuel, that is YOUR bad! MOBIL ONE 0W-30 will save on GAS as it reduces friction. WHAT PLUGS did you use! Do NOT use AUTOLITES< but use either BOSCH or DENSO iridium plugs! WHY?? because modern LOW SULFUR fuel REACTS with IRIDIUM and saves on GAS! If you are NOT getting 30 MPG's with this car, SOMETHING IS WRONG! They are VERY well made, and you will never see a TAURUS with bad wheel bearings, or using OIL! ALSO use ONLY energy saving tires, like MICHELIN HARMONY or CONTINENTAL ECO TEC tires! THese tires have LOW rolling resistances and SAVE ON GAS! They have more FLEXIBLE sidewalls and do NOT accumulate heat the same way as other tires do! ONce you get ALL the VALVOLINE WAX BASED JUNK OIL Out of engine, MOBIL ONE will restore power and smoothness! A CLEAN idle air control valve is necessary to keep the AIR/FUEL balance RIGHT! The TAURUS uses basically the DRUCK type of injection used on older BENZ engines! It uses a SENSOR that tests for AIR PRESSURE ( BAROMETRIC) CARBON In ANY egr valve is due to BAD FUEL USE and BAD oil choices! IN an IE|DEAL world of ONLY PURELY SYNTHETIC OIL< the EGR will NEVER accumulate tarry sludgy COKE like deposits! They will be REMOVED by AMSOIL POWER FOAM! If you are NOT using DENSO IRIDIUM or BOSCH FUSION Plugs you are wasting POWER and FUEL every second of driving! They burn MORE fuel MORE completely! You will TELL the difference if you follow these FOUR rules! CLEAN T body and IAC, MOBIL ONE or PENNZOIL ULTRA oil, FUEL EFFICIENT TIRES< and IRIDIUM PLUGS from BOSCh or DENSO! AIM for that 30 MPG goal! POWER WASH whole engine bay with GUNK ORANGE cleaner to remove ROAD SALT and any leaking fluids from MOUNTS and RUBBER hoses and belts! KEEP IT CLEAN under the hood! Run AMSOIL and GUMOUT through your PCV valve to clean the COKE from your PISTON RINGS and oil control matrices! STOP USING CHEAP OIL CHANGES! AMSOIL for FORD engines is good for 25k miles between changes! PENNZOIL ULTRA gives a 15 year 500k miel OIL WARRANTY! YOu only need ONE oil change each year on BETTER OILS! BAD OIL wastes energy and mileage! You will TELL the difference once your IAC has been removed and cleaned up! This will also protect your CONVERTERS from failing! GOOD LUCK!!
Curse those EGR valves, if it turns out to be that get the gasket with the screen to keep it from happening since recurring carbon chunks can stop the EGR valve from closing again at any time.
Car has rough idle when I'm sitting still in either reverse or drive. When in park or neutral the car idles perfectly. It's my gf's car 96 Taurus. It idles around 800 rpms and chugs but won't die. I put in new spark plugs less than 2 months ago...Also has new battery, alternator, and starter not that that is the issue. Any help would be appreciated.
