Bogs after running almost perfect

[cculver88]

So I have a 89 240sx with a 92 stock ka24de. So far I have replaced (on the motor) plugs, wires, fuel filter (z32), fuel pump, 02 sensor and the coolant temp sensor. Today I timed my car +5 advanced timing. It was idling semi rough but still had great power before I re-timed it. After I re-timed my car I took it for a short drive around the block. I was cruising in 4th gear at about 35mph. So I decided to drop to 2nd gear and see if I had gained any more power and to check smoothness of the motor under full throttle. The car bucked for a second then woke up and picked up speed until 7k rpms when I shifted into 3rd gear. When I got into 3rd gear I had barely any power and my motor was shaking violently. I pulled over and checked to see if I had knocked something loose when I shifting into 3rd gear. Everything was still hooked up and looked to be ok. I took the car immediately home and started to trouble shoot. I found nothing wrong that I could spot. My car had ran great before tweaking the timing today. I even moved the timing back to where it was originally set at. I am stumped on what to do or what to check out. Any help would be appreciated. I plan to check my ecu tomorrow and double check all my wiring again.

[cculver88]

also my car would idle at 900rpms before i messed with it, Now it studders at about 500-700 rpms when the timing at the same exact spot it was originally timed at.

[sx moneypit]

Sounds like you may have broken something in the engine.A compression test would be a good idea.

[cculver88]

So I got it running OK again. Turns out when I took my stock intake off to seal up some vacuum leaks I accidentally plugged up a vacuum line that I needed. Also one of the connectors to my coil was unhooked. So I fixed those two problems and cleaned my MAF. But here is the problem that I have now. I have power again but the car still doesnt have full power until about 5k rpms. You can definitely feel the power gain under WOT when you reach the higher rpms. I can still chirp tires into 2nd gear and the car pulls great but it feels like it's starved for fuel under WOT in the lower rpms. Could this be a weak fuel pump or maybe a clogged line? The only way I can think to explain this feeling is like the car has turbo lag. BTW its a stock ka24de.