Front wheel drive.
My LX has a 3.0 OHV engine (engine code 2) and is not firing on cylinder number five when idling. At speeds above idle, all cylinders appear to be firing okay, but the engine runs roughly when idling. I am getting normal mileage of 25 mpg on the Interstate at full speed.
The amber check engine light is on steadily, but if I am sitting at a red stop light for a minute or so, the check engine light starts blinking and the engine really gets much rougher. When that happens, when I accelerate to go at higher speeds with the amber light blinking on and off, the engine becomes so much rougher that I need to stop the car, shut the ignition off and re-start it to get rid of the blinking amber light and resume to the steady amber check engine light, when the only roughness in the engine is detectable only on idle, once again. The extreme roughness disappears after I follow this process.
Auto Zone did a free diagnosis for me, and two codes were detected;
1. PO316 Definition Crank sensor condition
Explanation the Crankshaft Position sensor signal is monitored for error
Probable causes - 1) Crank sensor defective
2) Check connector and wiring to sensor
3) Check trigger wheel for damage
2. The second code detected by Auto Zone was P0305
Definition - Cylinder misfire detected Cylinder No. 5
Explanation the power train control module monitors the crankshaft speed and has detected a misfire condition.
Probable causes 1) ignition system fault spark plug(s), ignition wires, coil
2) vacuum leak
3) injector fault
4) high or low fuel pressure
So far, I have switched the following parts from my other Ford Taurus, a 2006 model;
The camshaft position sensor, ignition wires, new spark plugs, ignition coil, new fuel injector for number five cylinder.
I have checked as best I was able for a vacuum leak by spraying water on the hoses and looking for bubbles and installed a new fuel filter as a makeshift measure of alleviating some of the possibility of high or low fuel pressure. I also switched the mass airflow module with my 2006 model. None of the above has had an effect.
A compression test was done on all six cylinders. Number five cylinder measured in at the lower end of its acceptable range, but still acceptable. The other five cylinders came in at the upper end of their acceptable range.
I do have another problem with the car which might or might not be related to the above problem, and that is the fuel gauge indicator (mechanical) is intermittent. It shows either 0 fuel or actual.
I hope that you have run into this kind of problem before and will recognize it and will be able to advise me what to try next.
Tuesday, February 28th, 2017 AT 11:51 AM