Hey guys,

I just wanted to pass along some knowledge, you guys are always awesome with responding and maybe this can help someone.

The disco was misfiring on cylinders 2 and 3. Codes: P0300, P0302, P0303. Wires and plugs only about 4K miles old, so in my head I immediately ruled them out. (Dead wrong, we'll get to that)

I also developed a tick that sounded mechanical from the valve cover area, so the Rover was not very happy. The misfires and rough idle were very intermittent. Some days I would drive the Rover and it would be smooth, other times/days it would be terrible - I couldn't think of why.

After replacing the front driveshaft and driving it around I started getting constantly blinking CEL, very bad - damage to cats, etc. New misfire codes P0304. I let the truck cool down a bit and started tugging on the spark plug wires - a couple of them immediately gave some slack from the coil pack side. So they must've been installed incorrectly that many miles ago (by me) and since come loose/undone.

The next morning I ripped out the SAI tube and got my hands in there to check the wires, sure enough 2 wires completely off the coil pack. I spent a good amount of time making sure they were clicked in and snug. After that the Rover ran like a top. I bought new coil packs, new wires, plugs to install when I do the valve cover gaskets (just for good measure).

It just goes to show that even when you know in your head the cause is not one thing, it could very well be that thing. The ticking completely went away, probably the sound was due to arcing in the coil pack area. I took the rover out to the desert this weekend and she was VERY HAPPY:

 

Glad you found the problem and thanks for sharing.

 

What about the ticking from the valve cover area?

 

Must have been the loose wires arcing into the firewall - is my guess.

So it wasn't "mechanical" afterall.

 

The wires can also arc to the SAI tube which is grounded by its mounting to the rear of the intake manifold.