Question about 1996 Ford Explorer

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My expedition check light engine on code#po306

I changed thhe spark plugs on 12/08
the coils were changed last year. i also changed the egr
why is my truck still stalling?

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You have some sort of bad sensor. The check engine light will only come on for bad sensor or electrical problem. It will not go on if it is vaccum, fuel, or spark related.

Posted on Jan 30, 2009

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You need to see if there are any codes in the OBD system.That's a good staarting point.

Based on your description, and how on '89 6 cylinder Ford I had ran, I would think it was a throttle position sensor. But you need to check for codes, and last resort, find a copy of the Factory Service Manual (not Hanes, not Motors, not Chiltons) at your local library. The FSM's give you all the diagnostic checks that the dealer techs use.

Posted on Jan 30, 2009

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Stop in at autozone and have them read the codes .. it's free then repost the question with those codes


please take a moment to rate this solution thanks

Posted on Jan 30, 2009

  • Roberta Smith
    Roberta Smith Jan 30, 2009

    I missed that you did the codes... the general consensus is that you need to have a compression test on the motor as one the valves in that cyclinder may be weak or sticking

    Any work done on that motor recently ?


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1 Answer

Slow acceleration

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Have you changed the fuel & air filter,spark plugs,
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When that is done,check for codes,then vacuum

If it is over ten years old, the exhaust converter may
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Last check for cylinder misfires as those ignition
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Don't over look the egr valve

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My 2000 Ford Expedition 4.6l had a manifold seal blown and was leaking fluid in the sparkplug sockets. Seal replaced and spark plugs changed, now I am having to change coil packs because Im getting...

Faulty EGR valves do not cause "false" misfire codes. An EGR valve that is not closing properly can cause misfires (and misfire codes) but they are REAL misfires when this happens.

To understand this, you need to understand what a misfire is and what kinds of things can cause them. It is a very LONG list and I do not have the time or space to get into all that here.

You will also need to understand this if you are going to properly diagnose your misfire codes without wasting a whole bunch of money on parts that you do not need. MANY things can cause misfires other than spark plugs and ignition coils.

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Has it had a tune-up yet? (New spark plugs) If not, you're due. Also, have the shop test your coil packs - a very common problem with the Expeditions. I had my plugs replaced and No. 2 coil pack replaced recently for around $340. I'm a handyman, but would never attempt to change the plugs on mine myself - too much could go wrong- breaking a plug off, special tools, etc.
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Windstar 2003 engine jerking and spluttering only when driving.Now check engine light has come on

Check lights have been on all vehicle for 30 years,
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Check for codes
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The jerking could be ignition or the EGR Valve or both,
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Have to start somewhere & diagnose parts of one
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Unplug vacuum hoses at egr valve,plug them and test drive.

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Misfire on number 6. changed spark plugs and coil, still reads misfire on number 6

What vehicle?

Spark plugs never misfire, by design, Wear yes,that stresses the
ignition modules

If you have a coil, that is for all cylinders,the others fire okey !

We need your year,engine, V6, V8, etc, to help

You never change parts to solve any issue
That is called wishing,hoping,pushing,poking,

What code # did you get PO306?

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The engine hesition sometime 04 expedition 5.4

Most likely you have a bad COP (Coil On Plug) .
Maybe more than one. Very common ford problem for last 12 years.
If you get a MIL Light on the dash (the wrench),check for a PO300 Code.
A PO304 would be coil #4,PO306 #6 Etc.
Cyl 1 thru 4 on pass side
Cyl 5 thru 8 on driver side,front to back

Also hills cause a hi engine vacuum and thus a possible EGR Valve going bad. You can unplug the vacuum lines and plug, to diagnose that issue.

Also leave the EGR disconnected if your working on coil issues. Just note the MIL light will stay on all the time,and remember to check your 300 codes if you feel a hesitaton or miss.

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My was doing the same thing, it was an EGR valve and a misfire on the #2 cylinder which required a new spark plug and a coil pack

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Check engine light on

Here are some possible causes: PO306 means cylinder #6 only.

Possible Causes onepx.gif Setting Conditions onepx.gif onepx.gif onepx.gif onepx.gif
  • Air leak in the intake manifold, or in the EGR or PCM system
  • Base engine mechanical fault that affects only one cylinder
  • Fuel delivery component fault that affects only one cylinder (i.e., a contaminated, dirty or sticking fuel injector)
  • Ignition system fault (coil or plug) that affects only one cylinder

Jan 25, 2009 | 1996 Ford Explorer

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