How is this possible

[1ramrunner]

Hi,
I have an '09 Ram 1500 with 32,000 miles, it does not get driven regularly.
My check engine light came on the other day for the 2nd time in a year. the 1st time it lasted a couple days and then went out on its own. My MDS light did not come on when the CE light was on, but the truck would still go into that mode.
The light has stayed on now for a couple days and trips in the truck and no MDS light, but it will switch into that mode. I have not ran the code yet because I believe it will just go out again on its own like before. The truck is running much better with the CE light on which has me confused. My lie-o-meter was showing only 14.5 MPG from before, but now with the CE light on it is up to over 18 MPG. This increase in MPG would have me driving my truck more often, but I can't understand why it runs better with the CE light on.
Any ideas as to what is going on?
Thanks,
Jim

 

[Rick3478]

The computer thinks there is something wrong with the engine, maybe one of the sensors.
Should it run better with CE light on? Maybe, if the offending problem was causing it to make bad decisions about timing or fuel/air mix, and it is now ignoring that problem and making its decisions based on other sensors. Should it get better mileage? Again, it might, but it also might be emitting tons of pollution in the process.

 

[raygun9]

You dont want to at least pull the code to know whats tripping?

Also, 09 w 32k.... wow.

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[Vern76]

Could it be a fuel issue?

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