1984 Honda Prelude, Idles good when cold warms up and the idle goes to 1000rpms like it should but when it idles a little longer the idle drops to next to nothing and you can hear in the exhaust pipe that it is sputtering. It won't idle right again untill it is cold again. I've driven 50 miles and used 1/2 tank of gas city miles. Can you help. My E-Mail is Customer (name blocked for privacy)@yahoo.com. I am useing my sister-in-laws pc because I am dislocated from Louisiana. Thank you Bobby Ritz.

Optional Information:
1984 Honda prelude 1.8litre

Already Tried:
changed fuel tank cap,pcv. Carbs rebuilt 24,000 miles ago, air filter is good. Eng is very clean.