oxygen sensors

1999 Astro Van which oxygen sensors are recomended for this car getting close to 100000 miles have no codes but thought it was time to replace.

"If it ain't broke, don't fix it"..

However, if you really do want to change them out.. go with either AC Delco or Bosch.. AC Delco is what GM uses as its main parts supplier.. Bosch is also a great brand.. If you are looking for a good price, try either RockAuto.com or even Amazon.com... I called a local parts store about a drivebelt for my car, they wanted $80!! I went on RockAuto.com and found it for $35

Oxygen sensors react to changes in fuel mixture. They react from rich to lean, and from lean to rich. The faster the sensor can react to changes, the faster the ECM can adjust fuel mixture and the better your fuel mileage will be. Oxygen sensor reaction time slows down during its life. At 100,000 miles the reaction time has slowed enough to significantly affect fuel mileage. Ideally all three sensors should be replaced. The data from both upstream, (front) sensors is used by the ECM to determine fuel mixture. Data from the downstream sensor, (after the converter) is used only to monitor the performance of the converter.

Thank You for the information. What sensors are best to use & are all 3 the same ? Appreciate your help.

AC Delco & Bosch both make good sensors. The sensors are all the same on your vehicle but, harness length and connectors are different. Make sure you purchase the "direct fit" sensors...don't waste your time, money or sanity on the "universal" ones. Spend the couple of extra bucks and do the job right... one time.

AC Delco & Bosch both make good sensors. The sensors are all the same on your vehicle but, harness length and connectors are different. Make sure you purchase the "direct fit" sensors...don't waste your time, money or sanity on the "universal" ones. Spend the couple of extra bucks and do the job right... one time.
thanks once again Old Master:smile:

You're welcome. When you replace them, warm the engine to operating temp, shut it off and use the special oxygen sensor socket, your parts store will probably have it.