temp gauge and idle probs

first things first my car started doing the lame ass honda (bouncing) idle. I fixed that but now my temp guage wont stay where it should be, it takes longer to warm up and when i drive around the gauge drops back to nothing like its still cold, but my heat is hot like normal. thermostat? and could that cause an issue with my idle also help a da brother out thanx

thermostat…ect sensor…air in the coolant…one of those

Thermostat is stuck open hence your coolant is getting too cold because it is flowing freely through to the radiator. simple replacement

Bleed your coolant to get the bubbles out. If that doesn’t work remove the lower radiator hose from the thermostat housing and check if its stuck open or grenaded (I would replace it anyways if its never been changed). If that doesn’t work then its most likely the temperature sensor.

basically everything i told you first -___-