QuestionI have a 2000 K2500 Chevy Suburban with 70,000 miles. In the past several months, we've noticed the check engine light flashes whenever we've been driving at highway speeds (70+ mph) for awhile. The handbook that comes with this vehicle says that this means there is a misfire. We took it to a local shop. They confirmed a misfire in two of the cylinders and diagnosed the fuel pressure regulator as leaking and causing the misfire. They fixed this. After this was fixed the fuel gauge started acting funny--like reading empty when it had a full tank. The flashing light still came on at highway speeds as well. We took it back to the shop and they said that the fuel level sensor had a high voltage. I asked them about the flashing check engine light and they said that what this really means is that there is just a repeat fault and not necessarily a misfire. My question is, are they correct in telling me that the flashing check engine light is just a repeat fault--probably the fuel level sensor--and not a misfire? Any help with this would be appreciated.
AnswerSounds like they don't know what's causing the CHECK ENGINE light to continue to flash ON and OFF.
When a fault occurs the CHECK ENGINE light illuminates and you obtain the code thru diagnostics and fix the cause. then you CLEAR the computer of the CODE that made the light come on and IF they fixed the cause of the initial problem the light should NOT be coming back on AGAIN unless they did not fix the problem or you have another problem.
However, Whenever you work on a fuel system and have to open the system up such as removing fuel lines, etc, etc this canm cause the check engine light to stay illuminated and or flash on and off for 7 to 10 days afterwards until the fuel systems vapor system gets recalculated and then the light will go off and stay off.
One thing that can cause this is a LOOSE fuel cap and or a leak in any of the fuel lines such as the pressure, return or Vent lines. If ANY of these lines are not properly sealed the light may continue to either remain ON and or flash ON and OFF.
I would make sure that the above said fuel system is completly secure and tight of ANY form of fuel or vapor leaks and if the light does not clear up after 0 to 15 days, then you have either the same problem or a different problem which will require more diagnostics.
Make SURE the fuel cap is the ORIGINAL style cap that came with the vehicle as I have seen many people replace the cap with a locking gas cap and had constant problems with the fuel VAPOR system until they re-installed the original gas cap and within 10 days the light problem was resolved.
NOTE: IF the light EVER comes ON and stays ON, Get it diagnosed ASAP.
autohelp
