2005 ion-2/ check gas cap light came on.... I stopped the car(still running) removed the gas cap & tightened it back on. When I got in the car the gas cap message was off but the engine light was on. drove for a little while(car acting normally) then stopped & shut the car off for a few minutes. Turned the car back on...Engine light still on. Help.... Car is running normally...accelleration is ok. What is possible problem or Sollution? Thanks for your time. Marc

Maybe the cap was just not put on all the way

Then the Evap Monitor ran & did not find any faults

That monitor is the last to run & only does so every few days

Your timing was just when you needed it to run

Not likely.... But as you just put fuel injector in make sure your fuel cap is tight cause if its not the computer will detect a evaporation leak in the gas tank. So tighten the gas cap and drive the car for a few days & see if the engine light goes off .. If not get the computer scanner to see what's going on

Your code, assuming it was evap related, also means other issues aside from a loose gas cap. Your fuel system "closes" down to purge unburned fuel back through the engine. A loose gas cap will stop this process, as in why the check engine light will go on. Also, there is a vent solenoid, purge solenoid, fuel tank pressure sensor, and a charcoal canister that are involved. My guess, but if you have a bad vent solenoid, you may have symptoms like yours. Any "good" technician can test this for you.

3 wing nuts. here is the info needed.

Service Information

2005 Buick LaCrosse ' Allure, LaCrosse VIN W Service Manual ' Body ' Lighting Systems ' Repair Instructions ' Document ID: 1537542 Tail Lamp, Turn Signal Lamp, High Mount Stop Lamp, License Lamp, Backup Lamp Replacement - Rear


Callout
Component Name
Notice: Refer to Fastener Notice in the Preface section.
Fastener Tightening Specifications: Refer to Fastener Tightening Specifications .
Turn Signal/Stop Lamp Assembly Replacement - Rear 1
Nut, Turn Signal/Tail Lamp (Qty: 3)
Tip
Pull back rear compartment carpet to gain access to lamp.
Tighten
2 N·m (18 lb in)
2
Lamp, Turn Signal/Tail Lamp
Tip
Twist the bulb socket and pull inward to replace the bulb.
License Lamp Replacement 3
Screws, License Lamp (Qty: 2)
Tighten
2 N·m (18 lb in)
4
Lamp, License Lamp
Tip
Twist the bulb socket and pull inward to replace the bulb.

replace sensor at gas fill up tube

1. It could be a bad gas cap, they fail all the time
2. It might be something else, you need to get the codes checked.

The most common cause of this is the gas cap not being tightened completely after re-fueling or a worn rubber gasket on the cap.Remove the gas cap and turn it over and check the gasket if it looks like it's not worn put the gas cap back on and then tighten it until it clicks several times, then it make take a little while before the check engine light goes off. If this still happens shortly after tightening the gas cap have the check engine code read at an Automotive Parts store. Some stores have the code readers and they'll get what the code means and advise you at that point.

Best to rent a scanner and check for other problems. If ok, the scanner will clear the light. If you bought a vented cap, the trouble will remain until a sealed cap is installed.

There is an issue with the engine management in your saturn. If there is an Auto Zone around your area, have them scan the car for a DTC code which would indicate the issue. Auto Zone scan free of charge and can give you the step by step instruction to getting the job done to replace any faulty parts. Note: if the code comes back and a faulty gas cap, buy the OEM from the dealer. All others will fail with in one year. In the mean time open your gas cap and re tighten it and listen for at least three clicks when tightened. Good luck and hope this helps, keep me posted be glad to help.

disconnect and reconnect the - battery cable.