Engine running rought at idle won't stay running runs great at higher r.p.m. check eng. light comes on once engine is warmed up.

Clean out you idle air bypass valve with carb cleaner. P0031 air/fuel sensor 1 heater (B1)bank 1, p0603 engine control back up circuit,p1148 closed loop B1. Broken heater in upper O2 sensor is one if not all of your problems. Replace all of your O2 sensors & reset engine light.

O2 sensor

Possibly an idle air motor for your idle problem or a vacuum hose off.

-Check for misefire.

mai

check for low coolant level.check coolant overflow jug if it is empty, more likely air is in the coolant system.add more coolant to overflow jug until coolant level stay at cold full mark,dont over fill coolant overflow jug.if all is good, to be on the safe side, replace radiator cap,replace thermostat,if your engine overheat at a long slow driving traffic.or long stop idling, if cooling fan dont turn on more likely engine coolant temperature sensor could be faulty.

is there a rattle under the car like the cat converter is bad when was the fuel filter last replaced

Plug the vacuum line you unplugged and the idle should come back. Change your air filter and the map sensor. check for correct coolant level and replace the coolant temp. sensor. This sensor affects cold starting and idle through the ECU (open loop mode, rich fuel mapping and 1200 rpm idle) It should go to closed loop mode in the ECU once engine warm up is achieved ( lean fuel mapping and normal 900 rpm idle). Do not unplug anything else till you perform an OBDII scan of the stored fault history

Go to auto zone they check for free, then will know what's is next.

bad vacuum lines or need replacement fuel filter could even be a leaky line faulty fuel sending unit or check air filter ..start there first

is it carb, or efi ? and what size engin?