Now that I got your attention, I have been troubleshooting my 2006 Taurus with the 12V Vulcan for a while. I have done a few posts on here and I was trying to avoid this one but I'm officially at the end of the road... all signs are pointing to a bad PCM
. The car came with a clean CARFAX but I know it was in a wreck because it's got different fenders, over spray on the headlight wiring, cheap paint, and a cracked engine fuse box. For what I've done, here's the history for those who don't know (and all parts replaced are Motorcraft parts).
Purchased car with a cyl. 6 misfire and bank 2 catalyst fail. (P0306 and P0430)
Replaced all 6 spark plugs, wires, ignition coil pack and both catalytic converters w/new O2
sensors. P0430 went away but P0306 remained.
and it still failed but it added a start up misfire code (P0316).
Performed a compression check and failed. Pulled the heads and both were bad.
Replaced both heads, all gaskets associated with a head kit, water pump, thermostat, and fuel injectors. Code changed to a P0301 (cyl 1 misfire) and P0316.
Ran another compression check and all cylinders are now reading around 180 psi
. Checked for vacuum leaks with carb fluid and had no change to idle.
Replaced fuel filter, all 6 plugs and wires (again), Ignition coil pack (again), Idler Air Controller, PCV
, Throttle positioning sensor, and Camshaft position sensor, and I cleaned the MAF
sensor and Throttle body... Still have P0301 and P0316. Reason why I replaced the IAC
, and fuel filter is that the car has a problem where it won't always let off the gas when I take my foot off the gas pedal. Occasionally it holds an extra second or two which has cause numerous close calls. I also have an idle issue where it likes to idle between 800 and 1200 RPM
The car does not leak or eat oil. The car DOES drink anti-freeze but that is due to a leaking coolant line from the thermostat to the reserve tank at the reserve tank connection (I am replacing that this weekend). Leak is obvious and you can see standing fluid on the top of the reserve constantly. No fluid has been found in the cylinders.
Currently, the car starts ruff but smooths out after about 2 minutes and then runs almost perfect (or so it seems except the fuel economy). If the engine is warm then it starts with no issues. I have had problems where the car wouldn't start (it would crank but no start) for up to 45 minutes but the moment I reset the computer, the car will fire up instantly.
I've done everything I can think of before going after a PCM
. I swung through a Ford dealership today and they pulled the VIN
only to find that a Ford dealership replaced the PCM
and Harness in 2011. I also have a sticker under my hood from a non-Ford mechanic shop that says it replaced the PCM
Oh, also... If I reset the computer before I go on a long drive, I averaged 32 mpg (manual calculation, not computer) on the way there with the cruise set at 65 mph. Once I restart the car 1-2 times, I drove it back and it averaged 27 mpg with the cruise set at 65 mph. Same road, no differences. Then after I got back, I will average 23-25 mpg. Once I reset it again, it goes up until I restart the car a few times and then it drops again.
Today I tried an experiment and I put 2 gallons of gas in it. The fuel gauge didn't budge and the electronic miles to empty did not change. I drove 5 miles and shut the car off for 6 hours. I came out and it still read the same. Took off down the road and about 10 miles down the road the fuel gauge increased and the miles to empty jumped up 50 miles.
Today I also experienced 3 times where I lost throttle response during a turn. I was exiting the interstate on a cloverleaf and halfway through it, the gas pedal went limp and dropped to the floor, the throttle and RPMs dropped for a moment, I picked my foot off the pedal and pushed it back down twice and then it came back. This happened twice on the way to work and once on the way home.
I've check my fuel pressure and it's on par to Ford's requirements.
Things that concern me now though is that this will be the 4th PCM
in 13 years. Is there something that is causing the PCMs to fail? Is there anything I can check myself? Is buying a $590 PCM
from Ford directly worth it or can I just use a PCM
from the junk yard WITH MATCHING NUMBERS and have Ford reflash that one? Is there anything else that you guys think I should do or check first? Thank you for reading this extremely long post and I look forward to any assistance.
Here are my previous Forums for those who wish to know more: