Land Rover Repair: Exhaust valve, valve job, marvel mystery oil

Question
I have a 1999 Discovery V8. After sitting for 1-2 days the engine would start, but run very rough. It would sputter badly and only turn about 1500 RPMs.  After waiting about 20 minutes it would start and run fine.  This has happened several times with increasing frequency (and without sitting for days)  My mechanic says it is sticking exhaust valves.  Short of a valve job, what can be done?  

Answer
Hi Wayne,

if you truly have the sticking exhaust valve problem that has plagued series II Disco's, the only true fix is a valve job.

One owner sent me an email saying that there is an additive that can help with this problem :  Marvel Mystery oil  See... http://www.marvelmakeover.com/test.html

I don't know much about this but you could give it a try and let me know.

Best of luck,

JohnMc

NB: Rover's North has an excellent article on the sticking valve problem.  At least you would know what is going on and why a valve job is the only fix...so far.