My 91 240sx was acting funny this morning. I was just driving down my road and at a low speed. Then all of a sudden it felt like it was missing and when I came to a stop, it acted like it wanted to stall. When I revved it up, it would only go to about 3,000 rpm it's highest and would jump up and down...sort of sounded like a rotary. Also there was a weird smell coming from the exhaust. When I tried to go, the whole car was shaking and the rpm's were going up and down again. The car has been driving fine until today. It's just a stock ka24de 5 speed. I'm not sure what it is. Hoping someone on here can lead me in the right direction. Thanks!

 

check to see if your cat is stoped up "glowing red" would be a good sign and cps might be bad? broke off the crank pos sensor is on top of the tranny bell housing right behind the head

 

s13 does not have this sensor.
and when you hit 3k rpm's did it sound like the rev limiter was hitting or just would not go over 3k because if so it might be ur mass air flow sensor

 

Exactly, same problem my z32 had.

 

yeah it did kind of sound like the rev limiter was hitting. If it's the mafs, how can I check to see if it's bad? I was planning on boosting my car so I picked up a z32 mafs already. If mine is bad, do you think I can just use the z32 mafs instead?

 

im not to sure if you can just put it on and go.but i do know that they are like $15 on here. umm try cleaning it first with some carb cleaner it just might be dirty.and if you unplug ur maf sensor and start the car and it asks the same theres ur problem

 

limp mode?

 

Ok I'll try that. But you're saying a mafs for my car is only $15? where do I buy it from? and what is limp mode? I just tried starting it again and pushed my foot on the gas....it's more like 2500 rpm not 3000...and it definitely sounds like it's hitting the limiter. :/

 

Ok I just tried unplugging it and started it....still does it....is this a common thing in 240's?
also, forgot to tell you guys I made a custom cold air intake so all the air is coming through a cone type filter. Had similar problems before, but I just replaced my filter and it was fine.

 

my bad you can buy them from someone on here for like 20bux..

have you tried to clean it yet??