This morning on the way to work I noticed my srs light would dim as I press the gas and get bright as I let off it. Could this be an alternator issue? Last night I did unplug the + cable while car was running and car stood on fine. Cars idling fine as well I am In need of a tune up which I'll do next weekend. I also noticed today for the first tome my speedometer was actin weird maybe 3 times as I down shifted the speedometer would jump from 60mph to 40mpg and right back up to 60 which was my actual speed. Any input would be fine.