Yes and no. Your GMC Sonoma's MAP and O2 sensor might be defective, but we'd
recommend going over the basics first. HC amounts above 2000 ppm usually
indicate one or more cylinder/s igniting less then 50% off their fuel
content, indicating either no a spark condition, no compression condition,
or defective ignition timing. It is recommended to begin your vehicle's
diagnosis by inspecting the ignition system first. Make sure your spark plug
wires are all good, the sparkplugs are not worn out, the distributor cap is
not cracked, and the distributor rotor does not have carbon build up. Once
these things are verified, you can move on to checking the electronic
components (sensors). Definitely don't simply replace the MAP and oxygen
sensors without verifying they are defective using a multimeter or scan tool
first.
posted by SmogTips Support
