I finally had the car out for a good 30 mile haul. Im running an xfi system throttle body single plane w/fuel rails. Half way into the trip while cruising at around 2500 rpm every now and then It would stumble almost like a slight mis fire, not real jerky just enough to feel it. Kind of like it was starved for fuel. I started wondering if my under hood temp had something to do with it. I took the highway home and it didnt seem as bad but towards the end of the trip it happened a few times. Any clue where to begin checking it out?

Also running an a-1000 external pump, things were pretty hot back there too. Pump is behind the diff. Is it possible to have a fuel boiling problem in the rails?

Thanks Rich

it maybe a problem with fuel.since you got efi do you have a pressure tap on front of car. you can put a pressure guage on it and see if it bouncing around or drops below your cold pressure. if hot it drops thats your stumble all efi needs a mininum fuel pressure.even 5 lbs below that it wont run right.