My 240 won't go any faster than 15mph! Please help

[VinceSez]

A few weeks ago my car wouldn't want to accelerate past 15mph. This usually occurs when my car is warmed/hot. No matter how hard I push on the accelerator, it wouldn't exceed 15mph. Even if I were to put my car in neutral from a parked position, and rev it, the problem would still occur. The RPM itself, wouldn't rev past 2-3000rpm from what I believe. I just had my MAFS replaced with a used, but working MAFS that I bought from a local 240sx shop. I don't believe it's that cat because I had that replaced several months ago. My car has been in the shop for at least two weeks now, and so far they said the computer was throwing codes about the knock sensor, but they said that wasn't the problem. The next thing they assumed was wrong was a certain wire connecting towards the intake manifold. They said that I would need a new harness, valve assy-aac, and gasket aac valve.

Does anyone have an assumption of what could really be wrong with my car? I haven't driven my car for two weeks, and I miss her!

[naed240sx]

umm if the only thing limiting your speed is the rpm, why cant you get above 15? Couldnt you just shift at 2k? I you do shift early, what is limititing your speed then?

[VinceSez]

I have an automatic 240sx. I have no idea what's limiting my speed.

[killablue240]

honestly it sounds like a mafs problem when the mafs isnt functioning correctly the computer senses it and goes into default mode where it will still let you drive the car but will not let it go above about 2400 rpms if you have a five speed your all right but if your transmission is automatic it wont shift due to the low rpms. if possible try another mafs check the wiring to be sure its not loose or damaged and make sure there are no obstructions for the air cleaner and or intake. hope this helps

[naed240sx]

ok that explains it better, but sorry, im not sure what could be wrong. my integra did that after awhile after getting flooded, as far as the rpm thing.

[TheOne]

am thinkin MAFS too, try putting another ground to it, if not try another mafs.

[90SXSE KA24ET DREAMS]

tread-starter maybe your in limp-mode or something.

[lrb_2000]

same thing happend to me the other day.. my MAFS came unplugged, and I couldn't rev past 2k... so my guess would be on that too.

[VinceSez]

thanks for all the help guys! i already solved the problem. It was an electrical wire/sensor just behind and below the intake manifold. I think it was the aac or iic? but yea... i solved the problem and thanks again!