once a week a lightning bolt in parenthacise comes on on my dash

Electronic Throttle Control system. If a problem is detected the light will come on while the engine is running. If the light remains lit with the engine running your vehicle will usually be drivable, however, see your dealer for service as soon as possible. If the light is flashing when the engine is running, immediate service is required and you may experience reduced performance, an elevated/rough idle or engine stall and your vehicle may require towing. The light will come on when the ignition is first turned on and remain on briefly as a bulb check. If the light does not come on during starting, have the system checked by an authorized dealer. Although I would replace the "dealer" or "authorized dealer" with a quality independent shop. In my opinion anything with the throttle should at least be checked out.

bad battery connection could be at fault or your alternator is not putting out steady voltage remove it and have it checked. might save you a thumb on the side of the road some place.

I had the same problem happen to my Dodge 2500 Year 2003 on 8-30-2010. I took it to the garage and they started engine and it works fine, check engine light is no longer on and reg lightning bolt does not flash???????