So my truck is throwing a code for misfiring of cylinder 5. my truck has seemed a little rough, but its not limping or anything.

So it should be either the plug, plug wire, coil pack, or injector... right?


when i disconnect the 5th cylinder wire from the coil pack the engine stumbles so it seems like i am getting spark.

how to i check the injectors? my initial plan was to disconnect the wires and see if it makes a difference. I can easily see and access the injectors on the passenger side, but where are they on the driver side?

are they under all the intake ****? if so how can i test the injector?

 

Quick and easy way to test an injector.. a screwdriver. A nice long screwdriver or a set of mechanic's stethoscopes. Place the tip against the body of the injector while the engine is running and place your ear on the screwdriver, you should hear a nice steady tick. If you hear no tick or it is diluted when compared to the others, the injector is clogged or near failure.

If it were your coil pack, you would have a random/multiple cylinder misfire code, not just one cylinder. Plug or plug wire, possibly.

 

Not to highjack but what if you have a #4 missfire and a random missfire under 1000 rpm's code. Changed #1 injector after it went out, plugs, wires, coil pack. Cam position sensor?

 

Random misfire under 1000 RPMs usually results from a failing coil pack.

 

coil pack was replaced and made no difference at all.

 

The coil pack consists of three double ended coils, each shared by 2 cylinders. Pulling the #5 plug wire kills the spark on both cylinders shared by that coil. If you are getting a misfire on one cylinder only, it is probably not a coil pack issue. Check for fouled plug, cracked insulator, bad wire. If adding propane improves the misfire, you're probably lookig at a problem with an intake-to-head gasket leak or an injector problem.

 

^ thanks

 

I'd suspect a lower intake manifold leak, causing coolant
to leak into the cylinders and causing the misfires.
Pull the plugs on the missing cylinders and see if
the threads look unusually rusty. That would confirm
the coolant leak.....