I have a 2000 honda civic, i drove my car around one day with no issues, I parked it for about 2 hours and when i started it and shifted into reverse (automatic tranny) it banged into gear and when i shifted into drive (d4) it did it again with pretty much no acceleration,after gaining speed to car ran perfectly fine, the entire time to d4 light was blinking no mattter what gear I was in. The only way to get acceleration was to start off in 2 and shift into d3 then 4. Also along with this issue was a fast erratic idle. I parked the car and went to drive it about 3 hours later to see if the issue had stopped and it was still happening, i drove the car for about 20 minutes and the lights started to dim eventually with the car dying, as soon as the vehicle died the lights came back on bright as normal but the car would not start(as if i had a dead battery) NO CEL's WHAT IS GOING ON PLEASE HELP!!

 

The blinking D4 light is telling you that there are stored transmission trouble codes. Get your hands on a scan tool and see what they are.

See post 4 in this sticky thread for help:

https://honda-tech.com/forums/honda-civic-del-sol-1992-2000-1/how-pull-cel-d4-srs-abs-codes-code-lists-1901557/


Also check the ATF level.