Dodge Repair: cylinder 8 misfire, dodge durango, compression gauge

Question
hi I have a 2003 dodge Durango 4.7 brought it to a mechanic he said I have to buy a new engine because the cylinder is misfiring and is no good I was wondering if he's right or is there other things I can do to fix this problem he swapped the coils and the misfire stayed at eight don't know what to do thanks tim

Answer
Hi Timothy,
Did he measure the compression of that cylinder and compare that measurement to any other of the cylinders' compression reading? If it is 25% less or worse than the 'average' of the other cylinders' compressions then I would suspect the issue is mechanical and thus he would be correct unless you can 'live' with the misfire.
So that would be an easy type of thing to measure by means of a compression gauge that you screw into each spark plug hole and then crank the engine over (remove all the spark plugs, and also remove the ASD relay from the power box in the engine compartment, which is in the front row of the box next to the left front fender), and then put the gauge in each spark plug hole and see what the readings are when you turn the engine over via the starter motor. Record the reading of each cylinder after the third rotation of the crankshaft.  That way you would have an idea of the overall condition of the engine. If the compression is not that different on #8 then I would check out the fuel injector circuit/fuel injector/spark plug wire to the cylinder as the possible cause.
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Thanks,
Roland