My 2000 Disco2 has P1300 (multiple misfire), P304 (cyl 4 misfire) and P308 (cyl 8 misfire). My wife claims it came on after running over a large bump (it has also started raining recently).

The truck as new magnacors within the last 10,000 miles (installed by Cerrone's) and has had new coil packs.

I'm surprised to see 4 and 8 go at the same time and the misfire is consistent on those cylinders.

Any ideas? Where are 4 and 8 on the block? Both at the front? Both at the rear?

 

I see that 4 and 8 are on the same side. Would an induction system failure cause this? Or perhaps coil issues? 4 and 8 don't appear to be on the same pack.

Can water get it around the coils or something to cause this?