engine doesn't idle on 1992 Toyota Camry

the engine starts up really good when cold,then whe motor gets warmed up the rpm's go to about 800 this is when it starts running sporatick also cuts out when you step on the throttle till you get to over 1500 rpm;s.Engine runs great at over 1500 rpm's.Also had toyota put on new cap,rotor,plugs,and wires 5,000 miles ago.What do you think?Has 168,000 miles.
No check engine light has come on

Asked by for the 1992 Toyota Camry
Really need to pull any Check Engine Light Codes. This will help you really pinpoint the issue.
No check engine light has come on