i just put the ls in my 00 civic coupe. well at idle it runs fine. but as soons as you give it gas its backfiring threw the intake mani. checked all the injectors they got positive feed to them. all the o2 sensor are fine and plugged. i got all the mani sensor plugged.im pretty sure the distrubitor is wired right. my ecu is throwing a code but dont know how to pull it when you have a obd2 harness with the conversion harness to obd1.. its like when you give it gas its starving itselft of it.
i got good fuel pressure. no fuel leaks. vacuum sits at around 15 which in my d16y8 it sat a 22 same with my bro ls.im pretty sure that the cams and crank are aligned. i spent 7 hours tryin to figure this out. even my ase certified uncle is stumped.we took it for a ride it rides like crap in second and will not go uphill.
some ideals would be great because im all out.

 

Gonna throw some ideas out.

What is your timing set at?
Do you anything to check to see what your af ratio is at?
maybe your cat is clogged?

 

its not the timing we advanced it still the same thin,retarded it same thing.its running lean.cat fine. this is a freshly rebuilt motor. only thing that changed is that i put rods and pistons in.

 

the obd2 ecu is throwing just the malfunction vtec light. i tried using both ecu thats why i checked the code on the obd2 ecu.

 

before anyone says search i did found many of the exact same porblems but no answere. i guess they fixed it and didnt post what it was.