Low coolant?
Cooling fan not working?
Water pump not circulating water?
System airbound?
Radiator plugged or restricted?
Thermostat not fully opening?
Throttle plate stuck in open position
i found that in mine, it was the egr actuator
Check the fan control
Is it carburated? If so I'd check that out, might need to be retuned or something.
No, it wouldn't affect the idle unless you were somehow overheating the engine.
it maybe just a timing problem
Best guess without actually touching the vehicle would be the voltage regulator. on most cars this is part of the alternator. I would start by checking the voltage on the battery while the car is idling and while running ~2000 rpm
Common symptoms of a head gasket failure in a 1994 Oldsmobile Delta 88 include overheating, white smoke from the exhaust, and a milky or frothy appearance in the engine oil, which indicates coolant mixing with the oil. You may also notice a loss of engine power, rough idling, and coolant leaking from the engine. If you experience these signs, it's crucial to address the issue promptly to avoid further engine damage.
If overheating while moving it could be brakes dragging or emergency brake on or bad bearings in wheel. If overheats when idling could be bad timing, seized alternator or idler pulley bearings.
check the wires, if they are crossed up you get bad ilding. my aurora was idling around 1500 rpm's, but after having all the spark plugs and boots replaced it went back to around 600...see if that helps
Its not obtaining gas or the air filter allot of leafs or fiber in it that is giving the car more gas than needed.
Your thermostat is probably stuck preventing the flow of coolant to the radiator. This is an inexpensive fix.