I need to find where the coolant temperature sensor is located on my 1998 Chevy Astro van?

in the air intake hose

02 sensor is your oxygen sensor, 98 chevy astro carries 3 oxygen sensor. i belived your bad sensor is on the passenger side by the exhaust manifold but if not try the drivers side all the oxygen sensor for this van are the same. you need to go under the van to replace it, if is to hard to get it out turn your van for five minutes then turn it off and try again, be carefull not to burn your self. the one close to the catalytic converter is the downstream oxygen sensor ok, good luck!!!!!!

or maybe the bolts themselves require sealant under the head of each one..some do..did you follow the parts store readout for changing the pump.. if not go get one and review it.. there may be something we both have overlooked..

Hi try to disconnect the airflow sensor or check for a low fuel pump pressure...

Chevolet Astro fuse box diagram and description


https://www.autogenius.info/chevrolet-astro-1998-fuse-box-diagram/

the front sensor or "sensor one " is located on the drivers side in the exhaust Y-pipe, sensor two is located near the catalytic converter

They are the sensors that are in the exhaust. I believe that there are three in this van. Depending on what engine it has. They are the only sensors in the exhaust.

I agree, replace the Coolant temp sensor, it will have 2 wires going to it, Not 1. Usually located just behind the breather near the thermostat outlet.

This sensor controlles your timing and fuel to air ratio.

it is on the fuel rail on the engine its next to the fuel line conection from tank to fuel rail for injectors

Most vehicles use a coolant temperature sensor which is located near the thermostat directly connected into the coolant line, or near the thermostat housing, there are relays for the cooling fan which is usually located in the power distribution box under the hood.