P0304 no spark from coil pack

[xavi.ordonez]

Just bought 2001 Taurus 3.0 OHV Flex Fuel (u code engine) that runs rough at idle, CEL started to blink and came back to be P0304. (No 4 cylinder misfire.)

Very weak spark coming from coil pack JUST for Cylinder No.4 even after changing 2 New Coil Packs (just in case the first NEW one was defective), New wires, and New Spark Plugs.

Good Compression (i checked it)
No Cylinder Leaks (i checked it)
Good Injector (i checked it)


New Coil Pack
New Spark Plugs
New Spark Pug Wires

Check Engine Light has not come back but still runs rough and like i said the spark is very weak for Cylinder NO.4

Could it be the Electronic Control Module (ECM), but if it was shouldn't spark for Cylinder NO.3 be weak too.

[shorod]

What method are you using to determine the spark is "weak"?

-Rod

[xavi.ordonez]

I was using the Spark Plug Wire to Exaust Manifold Method.

I disconnected all wires from the coil pack, spark plugs, battery, crankshaft positionig sensor clean them all with Dw-40, blew compressed air at low psi to all connections. Double checked my firing order and coil to cylinder, also cleaned the Cranksharft Positioning Sensor (CKP) terminals. Re installed everything and everything looks fine now. Smooth running engine.

Thank You for the quick replay any-ways.

[danielsatur]

I like using CRC electrical cleaner + dielectric grease for electrical connections.