Ha. I'm going to take a stab. Without actually being sure.

I know it is secondary air injection. And it's an omissions lowering system. I think it re burns some gasses at startup to reduce the emissions during that time.

I could be very incorrect. I agree. It should mean "pipes in the way".

Edit dgi explains properly here. https://landroverforums.com/forum/discovery-ii-18/intermittent-sai-while-driving-77470/#post551510

 

Can't believe I actually looked it up. According to the Range Rover people, you can disconnect it and the car will run fine, albeit with a CEL on.

Secondary Air Injection... can you ditch this?

 

Hey man, don't hold me to that..I'm just a grease monkey..

 

http://m.harborfreight.com/inline-ig...not%20providedOk after a week of no codes the p0308 showed up today en route to harbor freight. Cleared the code, never came back. But I bought this ignition tester.
I checked plug wire for 8 and it was weaker, spiked brighter with each miss and erratic. Another plug was a strong, consistent spark light.

Definitely going to replace the wire and if that doesn't work going to check the coil. Hopefully not a head gasket leak, just had them done not long ago. Plus it has a rough idle still.

 

This. Just did the coils and a #6 wire myself. I really wanted to scream having to deal with that

 

Now that I've already pulled the plenum twice, and pulled the MAF and IAC valve, I've gotten used to what's what. Saturday I am pulling the plenum and changing both coils and the wires. As long as I get the two plugs off the coils OK, I am no longer worried about pulling off the plenum. Even got a new gasket for it.

Bittersweet feeling. Happy to know I understand my truck better, but kind of annoyed I had to do the repairs at all. Live and learn, right?

 

Resolved mine. I posted in the thread I started