Throttle Body

I have a 1989 Full Size V10 Blazer 4x4 350 When in idle it acts like its going to stall it lopes only when in park Can someone help me with this

Would that be a "C10" Blazer?

Is the idle RPM correct when in gear, or also very erratic?

Is this a TBI system?

I have a 1989 Full Size V10 Blazer 4x4 350 When in idle it acts like its going to stall it lopes only when in park Can someone help me with this

Ever done a tuneup?

Fuel filter
Spark plugs AC Delco
Cap & Rotor
Air Filter
PCV Valve

I have done a tune up and Yes this is a T.B.I system

It has new plugs wires cap and rotor PCV Valve T.P.S Sensor and I dle AIr control motor It is a V10 Blazer same body style as the k5 the V is for fuel injection