87 gxl NA 127k miles, on start up takes alittle over a second to start, sometimes almost drops idle instantly then revs up high until I tap the accel then it drops to 1.5k rpm and idles with a tiny bit of putting. New wirse, plugs, oil, and filter. Exhaust is not fully on front cat due to center hanger rust breaking, but sit on pipe with new hanger just not welded around yet. That's all the info, so any ideas?

 

That's the accelerated warm-up system acting normally. The system rev's the engine to 3000 rpm then drops back to 1500. If you are in gear or tap the gas, the system is deactivated.