Where is the mass airflow sensor on a 90 Chevy van g20?

On a 1990 Chevy G20 van, the mass airflow sensor (MAF) is typically located in the air intake system, between the air filter and the throttle body. However, it's important to note that many models from that era used a speed-density system instead of a MAF sensor, so you may not find one. If your van does have a MAF sensor, it will generally be housed within a plastic housing connected to the intake duct. Always refer to the vehicle's service manual for specific locations and details.