Im lost
I am getting a bucking. and hesitation. The car acts wierd. sometimes i get in the car after sitting over night and the car will drive ok for a while .. then it will start bucking below 2000 rpms. then once i get about 3000 the car runs the best .. I have to only use a .25 throttle otherwise i get this wierd rumbling and a bogging feeling/sound. like im getting a load of air but not enough fuel. If i take it easy and light foot the throttle i can make it to about 5000. at most..
In neutral i can rev it to about 7 and then it ill let off and try again and sometimes it will go up to 8. driving when i hit 5-6 it feels like i hit a wall. if i double rev , like hit the gas 2 times quickly the car stubles and sometimes stalls out . I found a vaccum line off. but i replaced the hose and it makes the car run worse. i was told it controls either the 5th or 6th ports. When the car is running one end is pushing out air , while the other does nothing. I rewired the fuel pump after not pulling enough voltage to the fuel pump. I also did a bunch of grounding. well after the rewire the car was semi driveable. I have regrounded the pump. Changes the tps and a whole lot
Plugs and wires
Air filter
oil and filter
new exhaust manifold back ( bonez hi flow with borla cat back)
T2 fuel pump, then a walpro fuel pump
Grounded the alt. battery, and dual grounded the pump after resistor was getting too hot
tps sensor
Idle adjustment
tps adjustment. but no matter what its stick on 2 ohms and tops out at 5 ohms
checked all the fuses ..
cleaned up exisiting grounds
fuel injector cleaner
pulled a 30 psi idle fuel pressure
18 psi hold pressure.
I dont know where to go from here.. I need some guidance. i was told injectors, i dunno. im lost ,, someone please help me !!

 

As the TPS wears it will develop dropouts in the resistance value.
This usually shows in the 1st 20% of the throttle stroke.
So, as you open the throttle the ECU suddenly sees closed throttle and RPM >1500, so it gives a fuel cut.

Unplug the TPS & put a needle type VOM on the orange & black wire pins, set at 1K ohms.
Hold off the throttle & work the TPS plunger through its full stroke.
The needle should swing smoothly from 0K to ~5K.
If you see the dropout, replace the TPS.

 

i have a brand new tps .. and it still runs from 2-5 ohms

 

update. i replaced the t2 pump with my walpro. now i pull a steady 30 psi. the car started surging .. like going from 2000-3000 up and down., i had pulled the map sensor off and tested that .. that came back a little high .. i didnt test it with the vaccum gauge cuz i dont have,. but i pulled a 4.5 volts on the d terminal with the vaccum gauge off. I also tested the fpr i didnt get any pressure whats so ever. might explain why i have no 5 th and 6th ports. not to mention when i pulled it off after not releasing the pressure in the system nothing came out . while i was testing i pulled the vaccum off the fpr and the car started stumbling. has anyone had this before??

 

something to check is the motor mounts... racing beat sells the engine brace... my car bucks if I dont give it smooth cluctch action in reverse or 1st.--- i need a new right(driver seat point of view) motormount , which makes sense as the engine wants to lift on that side.

your problem does sound like a fuel management issue... i hope you find out what is wrong.

 

Take your AFM off, and see if it is moving smoothly. (the flapper door if it is S4, and the cone thing if it is S5.)


I had an S4 that got tar in it, and it would run like that.

 

well the cone moves in and out .. sqeaks a little bit and it has like a loose spring sound .. is there a way to check to see if the sensor is functioning within specs??