1999 Ford Need Help Please?

[David]

I have a 1999 Ford Escort zx2 2.0 dohc 5 speed manual. Recently had all new clutch kit installed. When we drove it off lot engine and battery light came on. Ended up replacing alternator and battery. A few weeks later it started rough idling and engine light came back on. When the clutch is pushed in the idle runs smooth. Let it out the car wants to die even when in neutral gear. The dia. test says its running lean and it has a extremely strong sulfur smell to the exhaust. The plugs, fuel filter, air filter, and cat conv are all new or have been checked. Also has been checked for vacuum leaks