Compression Ignition Addict
Join Date: Sep 2012
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MPG's dropping, suspect batteries or ficm
I've been noticing my mileage dropping for the past few weeks, gradually. About two months ago I'd fill up, and my calculations would average 18mpg. Now I'm down to about 15. Not the end of the world but definitely noticeable.
I've also noticed when I first start the truck in the morning, my alarm goes off on my CTS letting me know the FICM voltage is low, but it only last seconds. Within about 5-8 seconds from cranking, the FICM voltage is at 48v. However, the dash lights and the screen on the CTS flicker a bit until I get down the road. This is why I suspect I may be having an issue with the batteries.
Driving down the road with the truck fully warmed up, the FICM voltage fluctuates from 47-48v at 60-65mph. At 70-75mph, it holds at around 45v.
Other than that, no other issues.
My plan was to take the truck in and have the batteries tested to see if they're the culprit. They're very new looking Motorcraft batteries but do not have a production date on them.
Is there anything else I may be overlooking?
2006 F250 6.0 XLT FX4 CCSB
MBRP 4" straight pipe with 5" tip
Studded and deleted
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1995 Ram 3500 Dually Reg cab 5.9 12v auto 2wd