Hello, My 93 Accord is hard to start every 2 to 3 weeks. When this happens, the check engine light comes on and D4 flashes until it warms up and I cycle power. The engine stumbles and doesn't want to idle until it warms up. Cold or hot ambient temperatures don't seem to make a difference. I recently changed the main relay which had cracked solder joints, I thought that would fix some of my troubles. The check engine code is 6 and then 12, also the D4 appears to give code 19 if that is possible, my repair manual doesn't show anything about the D4 giving you a code. Are these codes related? This has been going on for a long time, 1 or 2 yrs., very intermittent. Thanks!