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Old 02-14-2014, 07:10 PM   #1
13tech13
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P0171 intermittent, vibrations

Hello All,
Well it is in the title, 2004 2.3l engine, check engine light come on and off intermitently giving me the p0171 (lean mixture), I checked for some vacuum leaks and couldn't find any, I sprayed carb cleaner almost everywhere and no changes. Any ideas ? O2 sensor maybe ?
Also, engine is making the car vibrating when on idle and on the Drive position, is it the famous motor mount, or maybe just need a full tune up, spark plugs, fuel filter and so.
Any input is more than welcome
Thanks in advance
Seb


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Old 02-15-2014, 09:14 AM   #2
Milton
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Quote:
Originally Posted by 13tech13 View Post
... Also, engine is making the car vibrating when on idle and on the Drive position, is it the famous motor mount, ... Seb

To diagnose your motor mount:
- start car in park, e-brake on
- put a 2x4 or 2x6 on top of the saddle of your hydraulic floor jack, and position under your oil pan
- start to gently lift the engine with the jack, just an inch or two

If the vibration goes away/lessens, then it's a bad mount. A good upper right mount separates the engine from the "frame" with a hydraulic cushion. A bad mount collapses so the engine is resting on the frame transmitting all engine vibration to the frame. Lifting the engine with the jack restores the gap between the engine and the frame preventing the transmission of vibrations to the frame thus giving you your diagnosis.

If you are replacing the right upper mount, ONLY use a genuine Ford Motorcraft replacement. Give serious thought to replacing the other two mounts.

Regarding time for a major tune-up, if you do not know when the last one was done, then yes it's time.
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Old 02-15-2014, 06:03 PM   #3
13tech13
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Thanks for your reply, I will do that for the mount. By major tune up what do you mean ? I just did oil change and I wanted to do the transmission too. but I guess spark plugs, fuel filter and MAF cleaning.
Also could it be a bad PCV valve for the code ?
Thanks in advance

Seb
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Old 02-16-2014, 10:46 AM   #4
sykozis
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Check the PCV tubing....

As well as vacuum leaks, P0171 can also be caused by a faulty upstream O2 sensor, a weak fuel pump, a plugged fuel filter, faulty/dirty MAF.....

If you don't know when it was last done, replace the fuel filter and inspect the MAF for debris and clean if needed (should be a "how-to" somewhere). If you don't know when the plugs were last replaced....they should be replaced.

Fuel Filter should be replaced at least every 30,000 miles and the MAF should be inspected for debris and cleaned (if needed) at the same time or any time the air filter is replaced.

If replacing the engine mount (it's on the passenger side), it's best to go ahead and replace the dog bone at the bottom if it hasn't already been replaced. There's no reason to replace the transmission mount (it's on the driver's side) unless it's faulty.
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Old 02-16-2014, 08:16 PM   #5
13tech13
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Thanks, So in the order today I replaced the motor mount and Oh My, what a difference, the old one came in two pieces, no wonder why it was so bad ...
I changed the plugs, changed the fuel filter and also cleaned the MAF. Reset the light and it was OK for a few trips and the light came back.... So now Im going to check the PCV tubing, but i sprayed some carb cleaner all over it, from top to bottom and I did not noticed any difference. i will chck closer tomorrow
The engine is a 2.3, can I change this tube without removing the manifold or not ?
Thanks in advance
Seb
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Old 03-04-2014, 08:43 PM   #6
13tech13
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Just a quick up to see if anyone has some suggestions
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Old 03-05-2014, 07:24 AM   #7
Highball116
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The PCV hose is a real pain in the butt. The intake manifold has to come off in order to access the valve and hose on the oil separator. If your mileage is high, it's a good idea to replace it, since the hoses tend to split from oil contamination. I'll advise you that the plastic snap ring holding the valve in place is very likely to break, and I would buy one ahead of time. Also an o-ring for the oil dipstick tube, a set of intake gaskets, and new bolts for the intake manifold if yours are rusted.

Toby
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