My 1996 honda accord lx idels perfect in park,but when you put in drive it shakes and the rpms go from 1 to .5 .have replaced spark plugs,wires, pcv,and air filter.

-scan for trouble codes -check air filter --map sensor [clean if dirty ] vacuum leak --cat converter--fuel filter

Check your EGR valve, see if it's stuck open. Next look for vacuum leaks, then check cam timing. Check engine light on? If so, get the codes.

IT SOUNDS LIKE YOU BLEW A HEAD GASKET OR SOMETHING OF THAT NATURE, MAYBE BUT I WOULD GET EXPERIENCE HELP

Could very well be the main relay, limiting power to all the electronics in your car, causing the problems you've mentioned. Have it repaired or replaced.

motor oil leak

Ensure your spark plugs,wires (ignition coil and spark) and your filters (air and fuel) are within 2 years of installation It's erratic at 800 rpm as the engine is cold and they like the 2200 range for 3 minutes before they kick down on their own. Press the pedal twice before inserting your key. The owners manual states depending on the outside temperature, the engine will require more priming. Update if possible.

i am thinking that the 15 amp fuse is the fuse that protects the ecm circuit replase the O2 sensor wires and check the harnes for a shorted wire.

check the spark plug wires one may be damaged and grounding out, i had a simaler problem on a 96 accord ended up being just one spark plug wire

check the iginiton control module

check the throttle position sensor