My s13 lags when accelerating & doesn't start sometimes!! WHAT GIVES!!

[CalPolyKing]

Ok, so this all began to happen about a month ago, and I dont know whats going on. I just got it smogged and no codes came up.
1989 SOHC 240sx Coupe

When I start the car in the mornings it starts up fine, or after letting it cool down for about 2-3 hours. After about 10 minutes of driving the car starts to lag in acceleration like in this video.
http://www.youtube.com/watch?v=mLVGG0VH9Ok

If I try to start it up right after a drive somewhere I have to constantly be turning the key and gassing it for it to start. The motor starts but it sound like its not getting enough fuel to get going.

Also, when all this started happening my temp gauge also started twitching like its on crack in the video:
http://www.youtube.com/watch?v=OiinrIq5_IE

ANY HELP WOULD BE GREAT!! I have look around, but it seems no one had all these symptoms just one or the other.

[nieko]

try changing your coolant temp sensor.

its right near the throttle body.

its like 20 bucks or something.

[slider2828]

Yup and check your timing and also boost leaks.

[StalinDrift123]

also look at your fuel pump and fuel injectors, one of those might cause the problem of not feeding the engine with the right amount of fuel that is needed. for acceleration lag, check your transmission for anything like oils, see if your clutch and fly wheel is ok.

[CalPolyKing]

also look at your fuel pump and fuel injectors, one of those might cause the problem of not feeding the engine with the right amount of fuel that is needed. for acceleration lag, check your transmission for anything like oils, see if your clutch and fly wheel is ok.

Well, I know its not the tranny because all the gears grab fine, it has something to do with the fuel. Thanks for the input, ill make sure to check my fuel pump and fuel injectors.
Anyone know if the Throttle Body Sensor is faulty it should light up on check engine? No? I dont want to replace a sensor that doesn't need replacing

[slider2828]

FSM... check your sensors... Its easy....

[HPKMotorsports3]

sounds like your fuel pump....check your injectors as well drop your tank it might be full of unwanted goodies...also buy a bottle or two of fuel injector cleaner

[CalPolyKing]

OK, I replaced the fuel filter, and it the temp gauge no longer jumps around. It still lags and I have to literally floor it and hold it there for the car to start up after the motor is warm, when its cold it starts up fine.

Im goin to replace the
-Coolent temp sensor
-O2 sensor
-Throttle Position Sensor

-last if the sensor replacing doesnt work I will do the fuel pump, but I really dont want too

[zenki.life]

fuel pump is as easy as unbolting bolts and pulling it out. whats there to be scared of?

[CalPolyKing]

The unknown...lol... I just haven't done it before, and the pump will run me 40 bucks in comparison to junkyard pocketed sensors which are free.

fuel pump is as easy as unbolting bolts and pulling it out. whats there to be scared of?

[gmember240]

let us know where you're at after replacin the sensors