Not your everyday HELP thread come on in give me a hand

[Delearious02]

So I have a ka24E 89 240sx that i traded for and its just sooooo slow I have had atleast a dozen 240s and most of them have been piggies so im no stranger to the 240 world but this damn thing has me STUMPED. So here goes.... The car revs kinda slow but smooth but there is no power barely enough to get to speed and not enough to get on the interstate safely so i think to myself lets check sensors and timing.... Ok so i did a tuneup new cap rotor plugs wires and still nothing... so I replaced the fuel pump the fuel filter the maf the iat the o2 sensor the tps and STILL no power!!! WTF sooo I was driving the other day and I double clutched it and WTF there was power it ran GREAT then i goto shift and shift normal and boom no power I double clutch again and power but then i slow down and make a u turn and then double clutch and its slow again and i try to double clutch and its still slow.... SOOO im stuck I have done everything i can think of..... what do you all think?

[lovenMy240]

kinda dumb awnser. but did you adj. the dissy (timing light). maybe it keeps jumping back an forth when you run the motor hard. maybe the boilt to the dissy is loos

[Delearious02]

Oh i wish it was that simple i soooo wish

[jbracy7]

pilot bearing/ shift fork not working right

[Delearious02]

Can you give a reason why u think that would be it?

[Kujo II]

if you've got a high mileage motor, unbolt the cat and run straight from the header... see what happens. As far as the transmission bit, you could have a seized shaft, but if it revs lazily in neutral I would dismiss that pretty quickly.

[locoluna825]

Do you have an engine light? Is this a real manual car? what i mean is it came that way factory?

sounds like the computer or something, (Kinda like the problem you get from an incomplete speed circuit). maybe... clutch is slipping, pressure plate isn't fully engaging? Hows your master and slave cylinder looking?
Modified by locoluna825 at 11:13 PM 11/27/2009

[Delearious02]

I have checked the exhaust the motor is suppose to have less than 100k on it and it is a manual and always has been...... checked the timing with a timing light btw forgot to say that ....

[Delearious02]

Found that if i diconnect the vacuume coming from the fpr the car runs great so i checked fuel pressure and its almost dead on but with the vac disconnected it runs great