Codes for all cyd misfireing and p0740 , p1750 , p0300 , p1399 and p1456 all spark plugs and coils changed does anyone kno what the miss fires could b ???

 

OOooo.. I be more worry about the 740 tranny code, you can check the coil and spark plug first.

But multiple misfire code can cause by variety of things, plugs, coil(s), valve adjustment, relay, list goes on..

 

^ I agree, you probably have only 1 or 2 cylinders that's misfiring. Pull the connector to the coil pack one by one to fine the misfire. When you pull the connector to the coil pack and there's no change in idle speed, that means that's a bad coil pack or plug. swap the coil pack with a known good one to narrow it down.

Trans

Try the following only after you fix the misfire and the trans is still throwing the trans codes.

You need to try and flush out the torque converter the best you can. Ideally, a 100 percent ATF exchange. Find a repair shop that has a newer style transmission "Vacuum exchange" machine that can change 100 percent of the ATF or close to it. Do not confuse this with the old style trans flushing machines. (This should be part of your regular preventive maintenance)

Replace the ATF external filter. (This should be part of your regular preventive maintenance).

Replace the Torque converter solenoid.

Replace the A/B Pressure solenoid.

 

Also, buy a new gas cap.

 

what spark plug brand were installed? some 2 buck specials or the correct $8 each NGK?

 

Start with the simple stuff.
Low or overfilled ATF level could cause those codes or Non Honda ATF used.

For the misfire the EGR clogged passage ways could be causing all cylinders to misfire.

Is it misfiring at Idle ?