Recently replaced my MAF sensor with an OEM Denso unit. Everything was fine; fuel trims near "0", AFR of 14.8. Went to drive the car today and the fuel trims were all over the place (+10 to -10), and the AFR varied between 12.8 and 17.4. Driving down the road, everything seemed to straighten out, then haywire again at idle. The car seemed to run okay otherwise, and there were no codes. The battery voltage from my OBD Torque program, with the car not running was 11.8 with the ignition on, and 12.2 with the ignition off. When running, the voltage is 13.7. I've had the car for three years with the battery installed by a previous owner, so its age is unknown.

Worth changing the battery as a precautionary/proactive measure? Is an AGM battery worth the extra $$$?

Thanks.

 

The battery should have a date code on it for when it was produced and typical life is 3-5 years. I would take it to Advance or AutoZone and have them check the battery& charging system and go from there.


Yes AGM is worth the extra cost

 

If you are willing to do a bit of work, if the old battery is "conventional" (not AGM), you can try and refill it. Pop the top and top off with distilled water. You could get an extra fraction of a Volt, and make it usable for a few more weeks. Maybe. Caution applies, sulfuric acid and all that...

 

Thanks everyone. I'm going to look into replacing the battery as a precautionary measure. It's at least 3-4 years old which makes it a potential liability going forward. Not a huge expense, and it might keep me from being stranded on the road. Hopefully, it also corrects the crazy readings I'm getting on AFR and fuel trims.

Well, at least I had almost two weeks without problems.