What are the probable causes of DTC P0316? - 2003 Ford Taurus

http://www.aboutautomobile.com/DTC/P0302

http://www.aboutautomobile.com/DTC/P0316

replace coils

Code 301 is a cylinder miss on cylinder one, and 316 is a miss detected during startup which is probably caused by code 301.
If the plug is firing, you could have an injector problem on that cylinder.

The first problem you have is assuming that the ignition coil is the only thing that can cause a misfire.

Diagnostic Test Code (DTC) P0316 is a "continuous memory only" code that indicates that there is a fault causing a misfire during the first 1000 revolutions of the crankshaft immediately after engine start-up. This should be accompanied by the regular cylinder misfire monitors (Codes P0301 through P0310) unless the misfire does not continue long enough for the regular misfire monitors to determine which cylinder is misfiring.

In order to determine what is actually causing the problem, you must have access to a scan tool that can perform Key On Engine Off (KOEO) fault testing and Key On Engine Running (KOER) fault testing as well as interfacing with the onboard engine computer to read live data and perform system tests.

Please note that generic OBD code readers DO NOT have the capabilities to do what you need to diagnose this problem. You will most likely get additional DTCs that can help lead you to find the source of the problem when KOEO and KOER tests are run. Generic OBD code readers can access only continuous memory DTCs.

Possibilities/conditions/systems that can cause this code are:
>Camshaft Position Sensor
>Low fuel: less than 1/8 tank
>Stuck open EGR Valve
>Blocked EGR passages
>Ignition system
>Fuel Injectors
>Fuel injector control circuits
>Running out of fuel
>EVAP canister purge valve
>Fuel Pressure
>Evaporative emissions system
>Base engine (mechanical) problems

OK, We'll cover the Diagnostic Test Codes (DTCs), starting with the standard definition set by SAE J2012 (Revised December 2007)
DTC P0171 "System Too Lean Bank 1"
DTC P0174 "System Too Lean Bank 2"
DTC P0301 "Cylinder 1 Misfire Detected"
DTC P0305 "Cylinder 5 Misfire Detected"
DTC P0316 "Engine Misfire Detected on Startup (First 1000 Revolutions)"

The "system lean" codes are pretty much telling you that there is way too much oxygen in the exhaust. There is too much oxygen on BOTH sides of the engine, and that is why you are getting codes for bank 1 and for bank 2. Bank 1 is the side where #1 cykinder is located and Bank 2 is the opposite side.

The misfire codes are pretty self-explanatory. #1 and # 5 cylinders are misfiring. The P0316 DTC is telling you that the misfire monitor is detecting a misfire as soon as the engine starts. This tells you that it is a very severe misfire and that the engine does not have to warm up and the car does not have to be driven to detect the misfire.

A misfire can be caused by many things it can be vacuum leaks, bad spark plugs, bad ignition cables, faulty ignition coils, fouled or malfunctioning injectors or injector circuits, blown head gasket, cracked cylinder head, burnt valves, etc.. etc..

However, look at the codes you have. Then look at the firing order for your engine. 2002 Mercury Sable is only equipped with a 3.0L 2V 6-cylinder engine.
The firing order is 1-4-2-5-3-6

Now if you take the firing order and split it in half, stack the two halves on top of each other, it looks like this:
1-4-2
5-3-6

When you look at the firing order this way, you can see that cylinders 1 an 5, 4 and 3, and 2 and 6, are "PAIRED" cylinders. They are exacly opposite in the firing order. Now, the cylinder only fires every second revolution of the crankshaft. With paired cylinders, one of the cylinders in the pair will fire on the first revolution and the other cylinder will fire on the second revolution.

Looking back at your codes, please note that the cylinders that are setting the misfire codes are paired cylinders.

Now the coil pack for your ignition is actually made up of three coils. Each coil fires a set of paired cylinders. If you look at the top of the coil, it will usually be marked with the cylinder numbers that each coil tower is supposed to connect to. The coil will look just like the firing order split and stacked as above.

With all of this said, I would say that it is VERY LIKELY that your misfire codes are being caused by a defective ignition coil.

The lean codes are a little different.

These are USUALLY caused by vacuum leaks which allow too much air into the engine that is not getting measured by the Mass Airflow (MAF) sensor and causes the engine to be getting too much air and not enough fuel (running lean).

I would take a good look at all of the vacuum hoses and lines. Ford is notorious for getting holes in the rubber parts that connect the PCV tubes.

If you do not find any obvious reasons for a vacuum leak, then you may want to fix the misfire codes, reset the computer memory, and drive the vehicle to see if the lean codes come back again. The misfires COULD be the cause of the lean codes. In a perfect world, this is not supposed to happen because the misfire monitors setting codes will not allow the oxygen sensor monitors to run and set lean codes. However, I HAVE seen cylinder misfires that have caused lean codes.

I hope this helps you to figure it out. Good luck!

Diagnostic Trouble Code (DTC) P0306 means that cylinder # 6 is misfiring. DTC P0316 means that cylinder #6 is misfiring bad enough that the computer has detected it within the first 1000 revolutions of the crank shaft. (I assume that these are the codes you are talking about because there is no such thing as a code "306" or "316" for your vehicle)

To put it plain and simple, you have a dead miss in cylinder #6.

This could be caused by several different things and must be properly diagnosed to prevent replacing a lot of things that do not fix the problem. It could be something as simple as a spark plug that didn't get gapped correctly, or it could be something major like a valve in your cylinder head that did not get checked or fixed properly when the head was off.

Do you have another code in addition to this ?
The P0316 DTC is Misfire Detected On Startup (First 1000 Revolutions), which usually has another code set in addition to the P0316 code.

P0302 IS MISFIRE ON# 2 CYLINDER P0316 I THINK IS KNOCK SENSOR BUT IM OLNY 90% ON THAT

P0171------ system too lean bank#1
Po174------ system too lean bank#2
For these 2 codes, try cleaning the maf sensor (mass air flow), that is mounted in the big black hose that goes from the air filter housing to the throttle plate, if it is dirty, that will cause those 02 sensors to send a signal to the computor to lean the air fuel mixture. If cleaning it doesn't work, the sensors will probably need changing.
P0300---- Random/multiple cylinder misfire
P0316---- Cylinder misfire at start up---- first 100 revolutions.
On those 2 codes, you have to do some testing to find out why there is a misfire.
Possible causes:
dirty/malfunctioning injectors
weak coil pack
fowling spark plugs/wires
Low fuel pressure

Code P0316 means 'misfire detected first 1000 revs.'

You didn't specify where you put the seafoam (oil, gas tank, vacuum lines etc) It's very possible that the fuel filter needs changing and the spark plugs may very well be fouled. After seafoaming a car it's a good idea to really open it up to burn off the foam and residue.