My engine is making a knocking noise coming from the lower part by the oil pan. I just did a tune up on this the check engine light is on now, and the code comes up cylinder 5 misfire and low RPM misfire. The knocking noise is not always there it gets louder and quieter even when the vehicle is in idle, any ideas on what could be causing this?

 

Double check the firing order on the coil pack, and follow each wire back to its cylinder
Coil pack wiring
3 4
2 6
1 5
Front

Engine cylinder numbering
3 6
2 5
1 4
Front

After checking this THREE TIMES, I always get it right by the 3rd time

You can then check for a rod knock, very bad news

Engine off
Loosen spark plug wires on coil pack, they should still be connected by easy to pull off.
Start engine
Using rubber handled pliers remove 1 spark plug wire at a time and listen for the knock.
If knock goes away or gets very quiet when a spark plug wire is removed then that cylinder has a bad rod bearing, bummer

 

Thanks I Was afraid of that any chance it could be anything else?

 

another question on this should I continue to drive the vehicle or should I park it until I can fix it!

 

If it is a rod bearing then park it, if it breaks you will need a new block.

But tune up and rod knock would be a very very unlikely combo.

Rod knock comes from low or thin oil and rod bearing getting overheated and spinning in it's journal, spinning causes the oil holes to get cut off and then it really overheats and gets soft and a gap forms.

When cylinder fires the piston and rod are pushed down and close that gap rapidly, the metal rod striking the metal crank causes the knock sound.
If you remove the "firing" then knock will go away, well almost.

An exhaust manifold leak can sound just like a rod bearing knock, very similar.
And with the newer bearing materials and oil formulas spun bearings are not as common as they once were.


I spun a rod bearing 200miles out in the bush on an old V8, removed that spark plug wire and drove it out on 7 cylinders, didn't have to turn the crank or the rod, just replaced that one rod bearing.
That was back in the day when you could actually remove an oil pan on a 4x4 with engine in the truck, lol.

 

check this out cause this will cause headaches
Ford Ranger 3.0L Camshaft Position Sensor