93 ka24de engine bogs under throttle

[zsmizzy]

ive got a 93 hatch with a ka24de. ive been having a problem with it for the last two months now.
at first it would idle perfectly for about 5 seconds then die off. no matter what i did it wouldnt run. if i gave it any gas at all it died. we fixed that by cleaning the IACV and getting a new maf plug/rewrapping the wires going to the maf.
now it idles but if i give it anymore than say about 15%throttle it bogs out. doesnt die unless i hold it for longer than 2 seconds. but i cant give it more than about 15-20% throttle. it just bogs and sounds like it wants to die. if i let it idle again right after that it comes back and idles. idles at about 800 or so rpm.
also, i can rev it up pretty much to redline but only under that limited anount of throttle. sometimes it backfires pretty loud through the exhaust afer doing so. it runs rich but doesnt smell like straight unburnt fuel. just burns the eyes if its on long enough.
car has a megan exhaust, test pipe, injen intake, megan FPR and megan header. the MAF is GOOD.

it has fuel pressure, it has spark on all cylinders.
im at my wits end with this car.

does anyone have ANY ideas? even something stupid sounding? ill try pretty much anything at this point.

[biggie]

Vaccum lines intact? No leaks? O2 Sensor new(ish)?

[zsmizzy]

o2 is good.
there is potential for vaccum leaks but not enough to hear or cause a problem

[biggie]

Any vaccum leak is multiplied under throttle.

[zsmizzy]

i hooked a vaccum gauge up to it but it only reads about 15 psi. but it holds it. needle doesnt shake or vibrate.

[biggie]

At idle IIRC vaccum should be around 20.

[zsmizzy]

thats what i thought.ill check hoses again. thanks

[biggie]

Should be able to spray starter fluid around the hoses, if there is a leak it would change the idle for a second.

[jekl]

I know you said you have fuel pressure but do you know your pressure under load. I know that normally when fuel pumps go bad they just stop working. But, as weird as this may sound I have seen nissan 240sx fuel pumps that are worn out but not totally dead. Running pressure should be about 35psi and when the vacuum line to the fuel pressure regulator is removed it should jump to about 47psi. Its somewhat difficult to check because there is no schrader valve to quickly connect to.

[zsmizzy]

pressure it good. the fuel pump is brand new. and i took the megan FPR off and put the stock one back on the rail and it fied the bogging problem for the moment. having ignition and timing problems now. and vaccum is still only at 15 or so psi.

[Biggins240sx]

Done any timing work recently, almost sounds like dizzy is off a bit. Also try pulling the codes if any. Diagnose one step at a time

[zsmizzy]

got it fixed. ended up being a mixture of fuel, ignition timing and spark. just gotta time it and other small things to get it done and back on the road. thanks for everyones help.

[raven2345]

I know you said you fixed it and all, but just for future reference, the brake booster vac line likes to have unhearable (is that even a word?) leaks. And, I'm kinda surprised you never checked your TPS; just another thing to keep in mind.

[zsmizzy]

the tps was replaced with a new one, good thought though, took me while to get to that one.
ill check the booster line tomorrow. thanks for the insight