I had the batteries tested and sure enough they were bad. At only 39 months of age just 3 months out of there full replacemant warranty. I remember when a diehard would go 5-6 years. Sears pro rated the replacemant and i got a new pair for just $100.
The batteries in my 99 f350 psd go dead after sitting for a week. If i drive it every day they seem to stay charged. How do i test for bad batteries or a drain of the batteries. the batteries are 3 year old diehards.
A nice cold air intake might be the choice if your just looking for some more MPG's and a small boost in performance. It is an amazing difference between the stock and my afe stage 2.