What's wrong?

Alright, for starters my car has 75000 miles on it and it is a 96 and i have a prob with it.  One, sometimes it will go really fast (low 15s) in the 1/4 and then all of a sudden go to crappy 17's tops.  What is wrong with my car?  Do i need to tune it up?  I already put a new dist. rotor, plugs, wires 300zx fuel filter,  and just change the oil.  Any other ideas for tune-up?

[ca18guy]

Is it the car or is it the person driving the car thats getting the quarter mile times. 17's are only a crappy launch away from the 15's. What do you feel is wrong with the car? How doe's it feel when it's not running right?

Sometimes it will pull all the way through the whole RPM range with smooth acceleration signing off at about 5500-6000.  But most of the time the acceleration will be bad and then pick up, almost like V-Tec or something, at 4000, pull like it should for about 500-1000 rpm then become erratic till finally about 5750-6000 RPM where most of the time it won't even want to get to redline.  Weird, huh?  I have no clue what it could be but the check engine light came on and said it had a random misfire.    

come on guys?!?!?!!?

[rubbersidedown]

buy a new engine :-)

[girliegirlS14]

what mods do you have?

[chinderer]

None at all

[drifterx]

is your clutch slipping or dying?
cuz those r milage u should start looking for a new clutch

[girliegirlS14]

what brand plug and what heat range was it?

[MingMing]

cheq ur fuel injectors?

[chinderer]

Bosch platinum +4 w/ the stock heat.

[chinderer]

I heard these plugs have their problems, should i get the reg NGK's?  Also, is an ignition rotor an ignition rotor or does $6 (the price of mine) sound too cheap? How do i check the fuel injectors?  Also, how much does a factory manual cost?  Could it need a new timing chain?

[chinderer]

One more thing, what is the EGRC - BPT valve cuz the comp said that was the prob too.