I have a 1995 civic ex with a obd2 ls motor obd1 distributer p75 ecu. I put b16 pistons with arp head studs arp rod bolts. The car idles perfect the problem is when u start to accelurate it gets real rough and starts to break up at 1/2 or 1/4 throttle at 3000 rpm's. In neutral i can rev it at 1/4 throttle to 5000 rpm's but if i floor it in neutral the car goes to 3000 and forces itself down and starts to break up at 1800. and here is the list of stuff i have replaced:
ECU
distributer
plugs
wires
tps
3 different map sensors
3 different throttle bodies
5 different engine bay harnesses
fuel pressure regulator
fuel filter
fuel pump
3 different sets of injectors
i've checked all fuse's
reset timing and it is now dead on
its a new timing belt
new headgasket

 

Im having the same problem in my eg hatch but I have a b16.. Are you throwing any codes?

 

double check that the mechanical timing isnt off a tooth and make sure your ignition timing is dead on

 

I would have said dizzy coil. but you've already done that.....

 

what do you mean by machanical timing but i no my timing is dead on

and my codes like jump around after driving for an hour it will say 43 1 and sometimes 43 1 42 and 6and sometimes 6 and 43 it's weird and if i figure it out ill let you know for sure thanks guys

and just replaced the altinator

 

Just did an alt. Sounds like a Bad connection and may be a bad ground

do you still have a CAT?

if so un hook it and start the car if it still runs like Butt the Check all grounds and see if you can hook the motor up stock like and get it to run right.

also did you just cross over the stock harness to OBDII and plug it into the OBDII Motor
or did you get a harnness from some place like Rywire.Com

also why not run a P28 ECU and keep the cars Harness stock so you can pull codes and chip it?

 

no bad grounds , no cat and the motor and harness are stock just pistons are diferent and im not chipping a ecu