hey there guys, i just purchased an 1993 240sx that is 100% stock with 243k miles. The problem im having after the engine get near or to temperatures the car has now power after 3500rpms, but if i stay on it, i can feel the power kick back in at around 5200-5800rpm.
Im stumped, i changed maf sensor and cleaned them both before use, (meaning i cleaned the used one i got before i put it on, and it was in alot better shape, looking wise)

The guy i bought the car from put new plugs, wires, distibutor cap and rotor button along with the fuel filter on it. from the 3 days of ownership ive learned it could be the following:

temperature sensor for the ecu not gauge.
Coil to distributor
clogged cat
Anything else?

In the mornings if i get right in and start driving it pulls like a beast then it gets up to temperature just after wrappin out first and second gear that quick and wont have any ***** after that.

 

well i just changed the coolant temp sensor and still no luck, someone please help i can afford nor do i want to burn this up or hurt anything.

 

Change your thermostat

 

its not overheating and the thermostat is opening cuz i just got done burping the the coolant system since i changed the temp sensor. its really wierd i can figure it out, once it hits around 3500rpms its like it pulling a 8000 pound load and runs outa *****.

 

mine acts like that too, not that bad but similar, when its cold, i pulls hard, then later it has no guts left. also yesterday out of no where it overheated. the antifreeze in the overflow reservoir was boiling. then i drove it today, and its fine, no overheating, so im in the same boat, i don't know. i still love my piece of **** though.

 

this **** is bugging the hell outa me, i just changed the coil,coolant temp sensor, cleaned the maf again, and even soldered the wires straight to the temp sensor since the plugs were covered in corrosion. and not a single damn thing, somone has had to have had this problem and fixed it before?

 

also i was going to pull the cat off to see if maybe it was clogged but the damn thing is welded so i guess that means somone has already changed it.

 

Changed the o2 sensor today and still nothing, damnit this sucks.

 

any updates??..cuz i have the same problem

 

bro thats a high milage motor.. have you performed a compression check.

 

Sorry ive been out for while but heres everything ive done so far

coolant temp sensor (ecu)
maf
o2 sensor
knock sensor (made a big difference but still not the way it should be)
cut the rear muffler off cuz it was full of crap (sounded like a bag of rock)
checked the cat
changed the coil
tested to tps

So far no luck, but the knock sensor i got was used and it did make a big difference, for the first 20 min or so i drove the car really hard and every time i got on it, it pulled like a beast, but then i started noticing the power going back down at 3500 rpm, and now it still loses power at 3500 to 4000 rpm it still has more than it did before i changed the knock sensor.

Also im pretty sure the compression is fine, an old lady owned the car and alway maintananced it and if the compression was low then it wouldnt pulled like it does first thing in the mornings or when i changed the knock sensor, also it wouldnt have as much torque as it does from 2000rpm to 4000rpm in 5th gear.

So finally im just going to take the car to nissan and drop it off and have them throw there computer on it and found out what it is in 5 min that i couldnt figure out in 2 weeks lol so when i get the car back ill post and tell you what they find and hopefully that will help alot of yall out.

 

do u have any updates man...?..i m still having the same problem