6.0 Fuel pressure gauge bouncing rapidly and rough running truck. HELP!!

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bmoore1488

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Jul 2, 2012
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Im new to the forum and could really use some help. I've had an autometer mechanical fuel pressure gauge installed for a while now and last weekend i was hauling a pretty heavy load of rock and the fuel pressure gauge started to jump from 40-65 so rapidly the needle looked like a blur and then the truck started to idle and run really rough. I came back and took the cap off of the engine fuel filter and air came pissing out. I did the compression check on the copper rings for the injectors and no bubbles at all. I changed both fuel filters and started it back up and it ran fine and the needle was very steady again for about thirty miles. I have since replaced the fuel pump and the truck ran better than ever before and the needle on the gauge was very steady, for about 50 miles and then the problem started all over again. It seems like the more i let the air build up the worse the gauge bounces as soon as i pop the top on the filter it quits for a few miles and then slowly progresses back into the same condition. Any Help or advice on this would be greatly appreciated. Thanks
 
Yea its def. sucking air somwhere in the system i just cant pin point it anywhere? Im currently living in SD. Im originaly from SC.
 
Well the air is coming in on the tank side of the pump. Does the issue arise with a full tank of fuel?
 
Duno how it could get air from the tank. Check filter orings.
 
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There is a quick connect fitting on top of the pick up tube assembly directly on the top the tank. I had a truck that had been fueled off a dirty in bed tank and the screen on the pick up tube was so obstructed the pump was pulling air in past the o rings in that fitting. All the filter o rings are on the pressure side so don't waste time with those.
 
Ok i'll try that then, i have already replaced both filters and orings anyway so that sounds like it could be it.
 
So i now think i had two separate problems. I have done the blue spring upgrade and replaced the fuel pump and installed a new fuel pressure gauge and i now have a very steady fuel pressure. But i still get a rough running truck at idle and going down the road every once in a while, when i do get it if i stomp on the gas for a few seconds it acts really muffled and sluggish and then all the sudden it snaps out of it and runs like a champ for a while and then the problem starts all over again. Im leaning toward the icp sensor now any advice??
 
Just for chits and giggles, check the wiring harness for chaffing, especially on the lead going to the EBS. Had mine ground out and gave a 'non-fueling' symptom.
 
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