well ive been chasing down this missfire...so i belive.....ive replaced all my ignition components over the year...and still get this frequently

the car tend to roun very rough...wants to stall...the other day it didnt want to start...so i manually primed the pump and it started right up

it doesnt happen right away....just after driving it fro a while and shutting it off and coming back to it ..it would run ****ty and die occasionaly

i get a small stumble at idle...btu nto enough to c teh guage move btu enough to feel

im at a loss i dunno what to do

soo i got my fuel pressure tested ......i get 45lbs at idle and it drops to 40lbs when driving......only thing i can think of is i have a bad relay that acts up once ina while....the fuel pump gets to hot and acts up......or my opti is slowly dying again throwing no codes...im mad...i dont want to go to a dealer....so would appreciate if someone can gove me a little bit of help
thanks guys

 

Try checking the fuel pressure after it sits for a while. It should hold to 40 or so for at least an hour after you shut off the car. Sounds like the check valve in the pump is bad.

 

explain teh check valve to me? thank you

 

A check ball, internal to the pump, keeps residual pressure in the line. One benefit is to make restarts easier.

 

thanks......my car is really agrivating me.....but i cant take it to teh dealer cuz everytime i take it in to get looked at they tell me its fine that they cant find teh problem...im gonna have someone hook it up to their laptop again and do some more extensive searching

 

where in relation to teh inside of teh pump is this? thanks