First off I would like to say thank you for having me in this forum and I'm new. So I was just given a 2001 Nissan Sentra 1.8 with a bad motor and trans for my daughters first car. This is the first nissan I have owned. So anyway I went to a local (orlando) jdm shop and picked up a qg18de motor and trans for it. Went back home and ripped out old engine and trans. Was decently easy to get em out. First thing I noticed is old engine headers have 4 02 sensors and new one has 2. Ok just swap em out. Next noticed old engine had egr tubes and different intake manifold got annoyed here kicked engine a few times and proceeded to swap those over as well as thermostat housing. Fun fun lucky it's a Florida car so no rusted bolts and everything came off easy. So got new engine into car and im hooking back up the wiring harness and I get to the camshaft position sensor. Old engine had just one sensor on engine head the camshaft sensor. New engine has 2 a camshaft sensor in same location and what I think is a cvtc sensor. My question is what should I do? Should I just leave it alone or do I have a connection somewhere along the line that needs to be extended to plug into that port? I'm not sure how to post a picture but I have one if someone can explain

Welcome to NICO Club! Are you trying to use the original wire harness and ECU with the replacement engine? I'm not sure it works quite like that. What year engine and tranny did you get?

Im using the original harness. The replacement engine is a qg18 also but imported from Japan. It didn't have egr and had different intake manifold etc. The question about those sensors I solved by switching the head plate that they were on. So yesterday I got everything hooked up and started it up and it idled fine it seemed. Took it for a spin and it seemed fine until I got up to about my guess is 2500 rpm ( cousin has scanner and car has no tach). It started bucking bad and had no acceleration until I let off the gas a bit then very gently pressed it again. This seems to happen every time I pressed the gas even remotely hard. So I drove it very gently to local advance auto and had codes scanned. Codes came up as p1130,p1140,p0505,p0403 and p0171. Question is what is causing the bucking

Sorry also the place I bought it off of couldn't verify the year or even specific car that engine came from. I know it's a qg18 but other than that....

Hmmm, a fuel cut can do that. Fuel cut is usually related to redline RPMs or top speed limiter. But, it seems like your main issue is the A/F ratio being off more than the ECU can compensate for. TPS, MAF, and O2 sensors affect that. Oh, and vacuum leaks. You've been into it a bit, so those vacuum lines could be jumbled possibly. Maybe look into the EGR stuff, since I saw your other post about swapping that system over. Sadly, I don't understand variable cams and timing much myself. Might have to do with that.