I will go get a new set of plugs. Ordered a leak down tester form harbor freight. Total cost was $48 shipped. The local mechanic wanted $50 to do the leak down test, so now I get a free tool.

Already ran compression check (forgot to mention it). Had 130 PSI.

 

Finally got around to doing a leak down test. Cylinder 4 checked good with 18-19 PSI of loss. Tried new plug - still throwing P0304

Should I take off the upper plenum and try a new injector? I sure hope it's not the darn coil pack....that looks like a real booger to get out.

 

I would replace the coil pack before a injector.
You still need to remove the intake plenum no matter what and a used coil pack is cheaper than a injector.

 

Thanks Spike that's good to know. Since I have to take the upper plenum off either way, I'll swap the injector to see if the code moves before I invest any money.

Are the coil packs easy to replace once you have the plenum off?

 

I have not replaced one on a Rover before but yes, they are very easy. Just unbolt it, unplug it, remove it.

 

Before you go and replace the coil, from what I've learned the coils run in pairs. If it was a bad coil pack, you'd be having problems with another cylinder as well.

 

What else is left as a possibility?

I just bought a used set of coils for $40 including shipping. Can't go wrong for this price. Will update with results after installation. Thanks for the help.

 

Foe-once you get this figured out PLEASE let us know, this is a common topic with DII's and nobody can ever report a cure.

 

Will do Spike - I owe it to you all for helping me

 

I'm anxious to hear the outcome myself, as I'm battling the same problem on my '96 DI. Its getting worse by the day too....