i have a 96 gmc 3/4 ton long bed with the 5.7L engine. typically will cruise around town ok. however when i try to excellerate too much, it spits and sputters and wont go. its almost impossible to accelerate while on the highway and pass someone. ive already replaced the mass airflow sensor. nothing. tune up. nothing. now i've removed the plenum over the intake and found a wet area near the rear of the intake passenger side. i turned the key on to engage the pump and pulled the injectors in that corner. none were leaking to my surprise. so i replaced the fuel regulator. $50 later, not including the mass airflow sensor and labor i paid for that and a tune up, it still wont hold pressure. when turning on the key, pressure builds to 50lbs. as soon as the pump stops humming, the pressure drops like a rock. pump is less than 2yrs old and may be the 3rd one i've put in it. ac delco too. help! im too broke for this crap!