Bought my Esprit with 22K miles. I'm up to 26K finally and had the #1 exhaust manifold gasket come out slightly creating that "fffft, ffft, fffft" sound. The studs, nuts and brackets had completely fallen out allowing the gasket to wiggle out. Apparently its a common problem. What I didn't realize until I fixed it was - even though I couldn't hear it at idle until recently - based on my greatly improved performance, it's clearly been a problem since I bought the car.
I fixed it yesterday along with the cam tower cap nearest the turbo that had also come loose slightly. What happened was pretty amazing; the exhaust quit backfiring almost completely and the ass-dyno says I have significantly increased my boost. Kind of a shocker. WIth all the mods to the car it's always been fast, but now it sounds significantly better, pops much, much less, idles better and the boost is definitely stronger.
Anyway, moral of the story; it never occurred to me to even check it because I had no idea it was a common problem. Wish I'd known sooner. So, if you haven't looked at yours lately, go check it!
Somebody tell Gmendoza I'm ready for a re-match :-).