96 Sunfire Too lean
HSCpowersports
03-16-2007, 07:36 PM
hi guys...hopefully you can help. We have a 96 Pontiac sunfire that is running terrible at 1400 RPM/35 mpH....scan tool says its too lean, but we have done everything in the book to solve this problem and have not been successful. Please help, maybe you will think of something we have not tried.
DeadBlade89
03-18-2007, 09:20 AM
hint: post this on the chevy cavalier section. ull be sure to get an answer.
GTP Dad
03-18-2007, 01:03 PM
Welcome to AF!!
There are several ites that can cause a lean condition. A bad O2 sensor, vacuum leak, bad fuel pressure regulator, bad fuel pump. I would start with the fuel pressure and make sure it is low you may want to change the fuel filter and recheck. If it is too low then you may have a fuel pump problem. If that all checks out alright then check for a vacuum leak. Too much air can cause a lean condition. If no lean condition then check for a bad O2 sensor as it may be reading wrong and not sending the proper signal to the computer to send the correct amount of fuel. The sensor may not set a light but it can be bad. Finally, the ultimate problem may be with your computer, ECM, but I doubt that since the car is just lean.
There are several ites that can cause a lean condition. A bad O2 sensor, vacuum leak, bad fuel pressure regulator, bad fuel pump. I would start with the fuel pressure and make sure it is low you may want to change the fuel filter and recheck. If it is too low then you may have a fuel pump problem. If that all checks out alright then check for a vacuum leak. Too much air can cause a lean condition. If no lean condition then check for a bad O2 sensor as it may be reading wrong and not sending the proper signal to the computer to send the correct amount of fuel. The sensor may not set a light but it can be bad. Finally, the ultimate problem may be with your computer, ECM, but I doubt that since the car is just lean.
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