Has a weak spark missing on 2 cylinders - Spirit Dodge Cars & Trucks

which engine? open hood, see engine which is it?
my wild guess, is someone using a scan tool got a DTC error
and saw the classic and common federal code P0301.
this was invented in the USA, and mandated by the EPA,
the Misfire monitor its called.
and means, only !!! that cylinder, #1 is weak on power.
that is its, dead or weak combustion on #1
this can be caused by 3 things.
1: the spark is bad on #1
2: fueling is bad in #1 (1 example, the injector is dead, or weak)
3: compression on #1 is too low.

no engine, stated, making all detailed checks impossible .
par for the course here..

miss fire can be a number of things weak spark plug damaged lead, faulty knock sensor or a problem with the injector.. clean the spark plugs check them for changes between them. there should be no real difference on them but black soot etc is a chance its over ritch. water getting in to the spark plug or a damaged rubber seal on the plug connector can also cause this problem so would check for this to. would say its the spark plug area my self.

A quick way to check the single coil pack if you know for sure which cylinder is miss firing and its setting a code you can swap the coil pack to another cylinder and see if the miss changes from one cylinder to another. If it travels to where you moved the coil then the coil is bad,if not you have other problems.

For engine misfiring problem check the help links mentioned below. Click the link below to go through the troubleshooting procedure :---- Engine misses and truck jumps? Hard to down shift? Issue with high gear only? http://technoanswers.blogspot.in/2012/02/engine-miss-and-truck-jumps-hard-to.html

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Bad miss at idle?

http://technoanswers.blogspot.com/2012/01/bad-miss-at-idle.html

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While stop engine idles like cylinder missing?

http://schematicsdiagram.blogspot.com/2012/01/while-stop-engine-idles-like-cylinder.html

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Engine Misfire codes for car?

http://schematicsdiagram.blogspot.com/2011/12/engine-misfire-codes-on-chevrolet.html
Engine Misfire codes?

http://schematicsdiagram.blogspot.com/2011/12/engine-misfire-codes-on-chevrolet.html

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Misfire on cylinder 4?

http://schematicsdiagram.blogspot.com/2011/12/misfire-on-cylinder-4.html

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Oil on spark plugs and car misfires?

http://technoanswers.blogspot.in/2012/02/oil-on-spark-plugs-and-car-misfires.html

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This will help.

Thanks.

Sounds possibly like a blown head gasket? Might want to run a compression test:)

MISSING CAUSED BY MANY THINGS LIKE BAD SPARK PLUGS, WEAK IGNITION COILS.STOPPED UP FUEL FILTER OR FUEL INJECTORS.WEAK FUEL PUMP.CHECK FUEL PUMP PRESSURE SHOULD BE 44 - 50 PSI.LOW CYLINDER COMPRESSION CAUSE MISSING.

POSSIBLE CAUSES OF MISSING AT LOW SPEEDS. WEAK SPARK AT IGNITION SYSTEM, BAD SPARK PLUGS + WIRES.STOPPED UP FUEL FILTER. DIRTY FUEL INJECTORS,VACUUM LEAKS AT HOSES OR AT THE INTAKE MANIFOLD, LOW CYLINDER COMPRESSION.

The most common misfire causes on the cars I've worked on have been:

1. Spark plugs
2. Spark plug wires
3. Ignition coil
4. Fuel injector
5. Wiring to fuel injector
6. Timing Belt
7. Vacuum leak or stuck open EGR
8. Contaminated fuel or bad fuel pump
9. Weak compression
10. Blown head gasket

Make sure your testing cylinder 8. Ford numbers their cylinders differently that others. #8 is the rear cylinder on the driver's side of the engine. The ignition coil may be putting out a weak spark. It should produce a spark capable of jumping a half inch gap from the coil terminal to the end of the plug wire. Next step without diagnostic tools is to swap fuel injectors with a good cylinder. After that check compression and compare with a good cylinder (hold gas pedal to fully depressed position before turning key to "on" to place computer in "clear flood" mode so engine won't run when checking compression).

If it ran good prior to spark plug replacement, then yes, I'd be looking real close at the plug wire to that particular spark plug. Perhaps it pulled apart inside boot upon removal. It may even be an indication that they are all getting weak, and time to think about a new set if it's originals.