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Topic Review (Newest First)
01-24-2013 06:04 AM
Z3T3C My ISSUE has been SOLVED!!! In fact, it was a fuel issue as suspected but left it alone, aside from changing the fuel filter. The issue: Fuel Rail Pressure Sensor, which is kind of like an electronic fuel regulator for returnless fuel systems. It took me $5 from a boneyard and 20 minutes to swap out the part and she has been running purrfect going on 2 days. New part would have been ideal, but I wasn't going to drop a $125 on a hypothesis. Gotta appreciate the boneyards.

LOL, I was just looking at my thermostat housing the other day and thinking the same thing... next thing on the list... flush, thermostat, hoses, and fill. BTW the Alternator is all good, my values actually have dropped a whole volt while driving after changing out the fuel rail pressure sensor, which I thought was weird. Although when it's time for the alternator it'll also be a good time to proactively change the cylinder head temp sensor.

Hope this helps anyone that may come across this with the same issue. Thanks again for everyone who offered help, I appreciate it and take care.
01-23-2013 06:59 AM
Classic6200 The DPFE caused me all types or erratic and intermittant issues. I also had a misfire and ended up changeing out the coil pack with an ACCEL and new 'live wire' plug wires and Bosch plugs. Heat can be a culprit that can change voltages as well as destroy plastic sensors and rubber hoses over time, especially as they get hot. I learned that even if it looked good, I should change it out due to the age of the parts. Along with the PCV valve and hose assembly, I changed both Oxygen sensors and cleaned all the connectors. Total cost was under $150 and now she runs like a stripped ape.

I plan on changeing the thermostate and radiator hoses this spring. My MPG's are around 26-28 pending my lead foot compared to 22-24 before the changes. Hopefully I'm good for another 130K til next problem

Don't forget about vacuum leaks. in my case it was several parts that were causing the problem.

Your misfire code is an electrical system error fault and not fuel related as far as I know. I also thought mine might be fuel related but I am glad I didn't go that route.
01-22-2013 05:51 PM
Z3T3C I have a DPFE go out my grandmother's 3.0L Taurus and that seem to make the car consistently run far more sluggish than what my car doing right now. I don't suspect it to be the case since this issue seems more sporadic, but its worth investigating. Classic6200, when your DPFE went out in your focus was it consistently running poorly it would it come and go and was it more so after the engine was warm? Also, after my wife drove it today, she told me the CEL came on. I pulled the code and it was P0303 for a cylinder 3 misfire. I'm still leaning towards a fuel issue since IMHO a spark issue has been ruled out, but I will report back on what I come up with. Thanks everyone for your suggestions thus far.
01-22-2013 10:14 AM
Classic6200 I also forgot to mention that I changed the DPFE. Sometimes you encounter multiple problems.
01-22-2013 04:21 AM
Z3T3C I will be looking into the alternator concern, because zapping electronic components is the last thing I want to do. Unfortunately, ATM we can't be without the Focus since my wife's daily driver is in the body shop for collision repair for the next week so she is using the focus while I'm back to driving the F-150. I can see why an increase in power would occur when applying brakes due to power demand for the lights, but I don't think it would cause it to jump that high. Also, I'm sorry but I can't seem to wrap my mind on how an alternator that is over-volting due to a bad voltage regulator but still charging the battery would cause hard starts on warmed-up engine. Why would it need help from the gas peddle in order to start as well as drop in RPMs and begin to surge or chug after the brake pedal is released? This wouldn't seem to be caused by an alternator issue as suggested, because starting the car is battery based not alternator based. You can start and run a car without an alternator on a fully charged battery for about an hour before the battery is out of juice, that's if you don't use lights and power devices. I know the coolant sensor if bad can cause hard starts on a warm engine, but would it also make it run poorly like it is?
01-21-2013 05:39 AM
mikebontoft Don't forget it only jumps immediately after a load with the brake lights. shouldn't be much but perhaps enough that when he lets off the pedal, the alternator is still charging more than it should for that split second.
01-21-2013 05:14 AM
whynotthinkwhynot High voltage = bad alternator. The voltage regulator is going out. This is one of the most common ways that this alternator goes out. I would suggest finding a local rebuilder- look in the yellow pages, call independent shops and ask, and maybe even some nice parts guys will tell you who rebuilds automotive electrical parts locally.

If you do feel like you have to go purchase one from a parts store, then I would suggest getting the cheapest one you can buy, and keeping your alternator to have it rebuilt locally when you have time to find someone. 2 reasons for this: 1) it should be much cheaper, like $80 instead of $200. 2) Local rebuilders use better parts because warranty repairs hurt their cash flow more than large chain stores.

You can also check with Village Ford, our new OEM supply vendor, to see if they have a decent price on a new Motorcraft alternator. You'd probably have to wait a few days, and I wouldn't suggest driving the car with an alternator that is giving over voltage. All you have to do is spike up to about 18v, and all sorts of things will be killed. Keep in mind that all of those numbers you saw were actually .2v higher at the battery. You're also probably not doing the battery much good either.
01-21-2013 03:42 AM
Originally Posted by whynotthinkwhynot View Post
Check the alternator using the electronic odometer trick so you can monitor voltage while you drive. Key off, press and hold the odo reset button. Turn key on, continue to hold button until odometer display reads [test]. Release button, now each time you press and release the odo reset button you will scroll through one of 30 test functions. Look for the one where the display reads [bat 12.1] or whatever your voltage might be at that time. The display will remain in test mode until you turn the key off, so you can start the car and now you'll be monitoring alternator voltage. If your alternator voltage reads 14.9v or more, then you need a new alternator. If it reads less than 13.2v, you need a new alternator.

It seems to me that your problem is vacuum related. You found the PCV, that is the most common vacuum leak or problem, however there must be some other leak somewhere. Also, once you do find the problem, it might help you to reset the A/F ratio- which the car will do anyway over time, but you can force it to do it faster. Disconnect the battery for 10 mins, I do this on a warm engine, now reconnect and start the engine. Do not touch the accelerator, and allow the engine to idle for 6-7 mins. During this time you will notice a slightly higher idle than normal- around 1k rpm. The idle will fluctuate slightly, but after the test is complete, the idle will drop to normal which is around 700 for both transmissions.
I did as you suggested. It was jumping from 14.7v-14.9v while night driving for half an hour. However, when coming to a stop 2 different times it dropped down to 13.4v and at a different time while driving from a stop light it spiked up to 15.2v, momentarily. Afterward, I was doing some further troubleshooting in my driveway, which I have determined the problem comes about after releasing the brakes. Whether parked or in gear as long as the brake is pressed it doesn't surge until it after the brake is depressed. The surge seems stronger and more noticeable when in park or neutral than when in gear. I tested it while it was in gear by applying the parking brake and not pressing the foot brake. Also, if I pump the brakes it spikes up to 1000 RPMs, after I stop pumping them it begins to surge. During this brake testing I did notice the voltage spikes up to either 15.4,15.5, or 15.6, but it was so brief and fast it was difficult to read and be certain.
I had the battery disconnected after the PCV hose replacement due to a new coil install, because immediately after firing it up it threw a DTC for a cylinder 2 misfire. So inspected the coil since the previous owner had new MC spark plugs and wires installed. The coil body was cracked all over, some cracks even had rust, and it was well out of resistance spec. Then, I had the battery out again for a good hour or more to clean the ground terminal connections from the new battery to the body (the location under the air box). Removing the air box allowed me to to discover that my trans mount, or lack there of, needed to be replaced.

Originally Posted by whynotthinkwhynot View Post
It's not likely to be fuel related. If it was, you wouldn't be able to drive the car.

What transmission do you have? What did you do with the TPS exactly? 2000 model vehicles have issues with TPS from the factory, typically the entire TB has to be replaced if it is the factory TPS. Parts stores will typically give you the wrong part, and the Ford dealer will freak you out with how much the right part costs.
It's the 2000 model year 4-speed auto trans, not sure of the exact transmission model though. I will take a look tomorrow. I had a CEL for the TPS, because previous owner had some bonehead mechanic replace TPS with ones calls for a manual transmission. This caused erratic shifting leading him to believe the transmission was failing. BTW, I had this issue posted in a different thread after coming up empty when searching the forums and Google. My issue was: If I was forced to go to with a new throttle body as Ford calls for I was just going to spring for the Focus Central aftermarket one, but wasn't sure which TPS part number I needed to pair it up with. I never got an answer, so I ended going the junkyard and getting a throttle body with TPS from a 2001 ZX3 2.0 Zetec with auto trans. During the same down time I ended up replacing my non-functioning IAC valve, because that was the other DTC I pulled after buying the car. Before replacing those parts the engine's RPMs were spiking close to 2K if I could keep it running.
01-21-2013 03:22 AM
Z3T3C I have replaced the upstream O2 sensor due to a possible non-reported, lean running issue (a suggestion by my father and old gear-head). I have to admit that as mad a bit of difference in running smoother. I also swapped out the fuel pump driver module due to a TSB from a different post in the forums. Car runs better than it has with everything I have dumped into her so far. Now it refuses to die now once I get it running, but can be hard to start without some persuasion from the gas peddle. Seems to be worse once the engine is at running temp. On a side note, since I replaced the driver's side upper transmission mount the entire car no longer shakes (a condition of 156k miles), but instead she purrs like a kitten as long as she is not struggling to stay running. After test driving her, the engine no longer surges and dies at stop lights or stop signs but does sporadically surges when is in park or neutral.
01-19-2013 06:23 PM
whynotthinkwhynot It's not likely to be fuel related. If it was, you wouldn't be able to drive the car.

What transmission do you have? What did you do with the TPS exactly? 2000 model vehicles have issues with TPS from the factory, typically the entire TB has to be replaced if it is the factory TPS. Parts stores will typically give you the wrong part, and the Ford dealer will freak you out with how much the right part costs.
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