I have a 1996 ford f-150 inline 6 4.9ltr. After a tune up I have noticed the idle stays up around 1100-1300 rpm after traveling and letting off the gas,then it drops to normallly under 1000 rpm and doesnt flutter <or vary>.
Is this normal? The tech at the local dealer says yes...I say no...it only started this after the tune up.

ps-The idle drops within 40-60 seconds...