Oxygen sensor

Hi all, I've got a 94 Astro and I was wondering how many oxygen sensors my van has. I thought it would have only 1, anyone know? Thanks

One (1).

Count your blessings. My '97 has 4.

I go to Mossy Chevrolet in Encinitas, and the Parts guy says, there is only 3 Oxygen Sensor..... I put the Car on the Lift, and found there was to be Four in my 1996 Astro Van 4.3 Vortex.... Seems even the Car parts People don't know what there talking about at even 50 Years of age... DO your Research, and ask questions..... then go get the parts at Napa.... for half Price...