Codes P0316, P0302, and P0171.. oh boy

Discussion in '2nd Gen - 2003 - 2006' started by Prince_Polaris, Jan 12, 2019 at 11:19 AM.

  1. Prince_Polaris

    Prince_Polaris Full Access Members

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    Okay, so I think I've talked about it before, but for a recap, my Expy's had some weird performance problems. For example, my MPG doesn't ever hit 10, and it seems like it's gonna dip underneath 9 sometime soon. Also, it seems... weak.

    For example, last year I went to morgantown for something, and every time we went uphill, it would lose so much speed that cruise control would give up- and I keep it set to the speed limit, 70!

    However, the most recent time I went there, it was totally fine, and only one hill gave me problems at all- I slowed down to 65 while climbing it. Still better than the first trip.

    And both trips are on the exact same route, too. And on the second trip, I had a heavy suitcase packed too! Anyway, in addition to this, I've had two different instances of the engine shaking at low idle. First time, the check engine light was flashing, but giving it a rest and restarting it fixed both problems. Second time, it flashed again, restarting did nothing, and the light stayed on.

    So since it actually kept the code this time, off to autozone I went, and I got those three codes. Misfire on startup [first 1000 revs], cylinder 2 misfire, and system too lean.

    What I want to know is, when I take the poor girl to the mechanic, what should I be telling them, if anything? And alternatively, is it even safe to drive? For some reason, the shaking seems to be an "either it happens or not" situation but I don't want to just drive around if I'm hurting it.

    And, my MPG is dropping, before it started these weird fits, it would hover around 9.4, now it's down to 9.2 and I guess it's gonna keep dropping.

    A while ago, I got the spark plugs and the vacuum lines fixed, which helped some of my performance and mileage, but ever since I bought the car I've never been able to get to 10mpg! Something's wrong...

    [​IMG]
     
  2. 1955moose

    1955moose Full Access Members

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    You've got 3 problems. 1, p302, your #2 cylinders misfiring, coil, plug, injector, 2, you've got a generic misfire, that 0316, and 3, you got a vacuum leak, your 171. Got to do the usual, replace plug, coil, boot for #2, smoke the motor to find your p171 leak, and the 316 may disappear fixing the other 2.

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  3. Hamfisted

    Hamfisted Full Access Members

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    I'd probably have the intake system smoke checked. The P0302 is a misfire on the #2 cylinder on the passenger side of the motor ( second from the front ...). Could be a bad coil if those haven't been changed lately. You said you had the sparkplugs done recently. The coils are cheap, and the #2 coil is relatively easy to change out. The P0171 code is a vacuum leak from a hose or leaky intake gasket on the driver's side. That is where the smoke machine earns it's money. If you don't want to buy your own, call around and see if a shop in your area has a smoke machine and can test your Expy's intake system for a leak. The P0316 code is just triggered when the total number of misfires hits a pre-set number ( like 1,000 or so ...). If you get the other two things fixed that will go away.


    -Mike
     
  4. 1955moose

    1955moose Full Access Members

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    I was looking the other day and saw smoke machines for around $50.00 on up. For that cheap, pays to do it yourself.

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  5. Adieu

    Adieu Full Access Members

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    #2 misfire is a classic for coolant leaks on Ford V8's, check for fluid in the spark plug well
     
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  6. Prince_Polaris

    Prince_Polaris Full Access Members

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    Weird thing is that I did have the vacuum lines replaced, remember the post I made a while ago about it?

    [​IMG]
     
  7. 1955moose

    1955moose Full Access Members

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    Theirs about 6 different things that will trigger that code. Look it up on google.

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  8. kb0jfg

    kb0jfg Member

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    Check elbow on the bak of the intake under firewall that goes too pcv valve array. I had a p0171 an the elbow was torn.
     
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  9. TobyU

    TobyU Full Access Members

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    I'd just stick new plugs and a new set of ebay $35 coils in it.
    Then find the vacuum leak.
    Our 2000 has an intake leak I am almost certain. Either a gasket or a crack. I get both lean codes but runs fine until it gets below 40 out. Then it surges at idle as it tries to keep rpms consistent.
     
  10. jim midd

    jim midd Full Access Members

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    I had a similiar issue with my '03 when i got it. i did a DIY smoke test with a cigar and some 3/8 tubing and found i had a bad vac leak around my resonator, somewhere I would have never thought to check otherwise. Replacing the tubing that held that on solved a lot of those problems
     

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