My na s5 has a weird stumble at a very light press of the throttle when your trying to maintain a constant speed. the car runs strong. But it seems to pop and buck.Just replaced the maf any ideas thanks

 

fuel filter, pump, or filter sock in tank. my tank needs cleaning out bad along with a pump sock. it causes my car to stumble or buck once in a while.

 

it has new 255 lph pump sock and filter

 

well i pulled code 17 feedback system what is this and how do i fix it

 

its an Na with a 255lph, correct me if im wrong but that is overkill for Na, your probably running super rich.

 

I was under the inpresion that the stock injectors would only push the amount of fuel the the ecu would let

 

Its surging? My auto n/a does that when idling through parking lots

so annoying

 

Feedback System code means the 02 sensor isn't being read by the ECU, which in turn means the ECU isn't going into closed loop. Fix the 02 sensors wiring. See the local series five FSM for how to correct fault codes.

A larger than stock fuel pump will overwhelm the stock FPR and force more fuel thru the fuel injectors, even though the fuel injectors is opening for the same amount of time as with the old pump. How much more fuel?? Got me, but it will be more than with the stock pump. Enough to cause your problem? Got me, never done that.

Or put another way.......the FPR is controlled by the vacuum put on it. It has no way to know you put a higher output fuel pump in, so it still opens only as much as it did before. The FPR was designed for the stock pumps output, not the higher output pump.

Still, I'm not saying the higher output pump is the problem.

 

thanks that makes sence now would you sugest getting a aftermarket fpr

 

I'm having the same problem with my corolla

but it's carbureted... so I don't think it's the same issue.