Aftermarket Additives & 100k mile maintenance

[70burntorangeT/A]

My 2006 taurus now registers 106k miles. Ive noticed about a 4-5 mpg drop here over the last 5k miles or so and occasionally a rough idle. It even died on me one time at low rpm (thankfully i was only doing 5mph or so) replaced fuel filter and that did nothing.  Spark plugs were changed at 75k along with wires as recommended by ford. Car has had the oil changed every 3-4k miles since new, always replaced air filters, ect. Basic maintenance. Someone told me to try some fuel injector cleaner (the 4 dollar a bottle junk at walmart that treats a tank of fuel) was going to do it and i was suprised at how many different additives there are for fuel, engine oil, tranny fluid, ect. Just wondering if anyone has used any of these additives and if any of them actually make a difference. Also is there really any other maintenance that should be done? Any ideas on what might be causing the drop in fuel economy? Car seems to still have good power (for a taurus), good compression, good oil pressure, and burns no oil

Thanks 

[Chryco Psycho]

could be an O2 sensor out of range adding fuel how do the plugs look ?
 I tried injector additive to "clean" the injectors it just turned the engine light on 

[70burntorangeT/A]

havent checked the plugs. May try to check a front one tomorrow as the 3 in front are very easily accessible. When it comes to modern cars and all their electronics i dont really even know where to begin  Thanks for the tip

[MOPAR FANATIC]

  try cleaning your trottle body with carb cleaner and a brush/compressed air.  also your I.A.C [IDLE AIR CONTROL VALVE] may be sticking,clean that also.i kow what you mean about all the electronic gizzmo's on these cars,sure can be a P.I.T.A TO DIAGNOSE............. 

[moparmaniac59]

Most of the injector cleaners are nothing more than diesel fuel. I just rebuilt the upper end of my daughter's Taurus (blown head gasket) 3 liter V-6 and purchased a set of refurbished injectors (ultrasonic cleaned & flow tested) for just over 100 bucks. A new set of injectors might improve your gas mileage. You gota pull the upper plenum to get to the side closest to the firewall, but it's a fairly easy job.


                                                                   Matt B.

[Chryco Psycho]

try cleaning your trottle body with carb cleaner and a brush/compressed air.  also your I.A.C [IDLE AIR CONTROL VALVE] may be sticking,clean that also.i kow what you mean about all the electronic gizzmo's on these cars,sure can be a P.I.T.A TO DIAGNOSE............. 

Absolutly , they get dirty clean them & it makes a big difference 

[dodj]

could be an O2 sensor

When o2 sensors go out of range, the cpu defaults to a richer than optimum setting (cuz it doesn't know where optimum is anymore). Could be the source of your sudden drop in mpg. They generally cost about $100 a piece. Your car may have one, two, or four. 

[hooD]

try cleaning your trottle body with carb cleaner and a brush/compressed air.  also your I.A.C [IDLE AIR CONTROL VALVE] may be sticking,clean that also.i kow what you mean about all the electronic gizzmo's on these cars,sure can be a P.I.T.A TO DIAGNOSE............. 

  your EGR valve could also be sticking causing vacuum issues and stalling.   Tap it with a hammer.

If you have never cleaned the throttle body it will definitely be carboned up.   Do you have the 3.0 ?

Have you ever cleaned the mass air flow sensor?  It has two very fine wires that can get dirty and send bad info to the computer.
carb cleaner and a Q tip will do the trick.  Tamper proof torx socket is needed to remove it.



O2 sensors usually throw a CEL (check engine light).  You didn't say if you have one.

[Oldschool]

Ok, I am going to throw a curveball into the mix here. I work at Fairground Automotive here in Georgia and we run across these type symptoms all the time. If the check engine light is not on, but you are experiencing a rough idle and a drop in mpg, I would suggest you have the ethanol percentage in your gas tested. Gas pumps at the filling stations have a label that say no more than 10% ethanol will be in the fuel your put in your car. When we run across symptoms such as you are describing and plug into the computer to look at the sensor parameters and they are all within specs, we stop diagnosing the issue and test the fuel for ethanol. We have run across as much as 16.2% in cars displaying your symptoms. 10% ethanol can cause these issues, but more than 10% will cause issues on non-flex fuel vehicles. If you can't figure it out, get a $15.00 test kit and pull a sample of fuel from a fuel rail. You might fix your problem for the price of a test kit and getting your fuel from somewhere else. BTW - the test kit will test fuel many, many times before you must get another kit. We find this tool to be very valuable here at the shop. It has bailed us out more than once.


Flex fuel vehicles can be plugged into thier computers and they will tell you the ethanol percentage without buying the kit. They can do it using the on board computer. Non flex fuel vehicles need the kit to test them.

Hope this helps......

[70burntorangeT/A]

Check engine light just came on this afternoon

[Oldschool]

Check engine light just came on this afternoon

It still might be a fuel issue. Bad gas will make oxygen sensors and catatlytic converters give readings that are out of spec, even though there is nothing wrong with the sensors. Especially if it is not a flex fuel vehicle. We see this stuff all the time....  0.02

[moparmaniac59]

Do you have a code reader?

[70burntorangeT/A]

Got in it this morning and the engine light is off now. Hooked it up to a code reader anyways and all that came back was "random misfires"

[Oldschool]

That sounds like ignition issues. Most likely spark plugs, ignition wires, or ignition coil/coils. 

[MOPAR FANATIC]

That sounds like ignition issues. Most likely spark plugs, ignition wires, or ignition coil/coils.

  I was thinking a coil pack is on it's way out.