HELP!!!!!rocker arm came off #4 cyl.intake side

[jbart423]

ok to start with let me give a description of the car.91 sentra ser , 97 fwd blacktop avenir engine,stock maf#22680-54c01 i have installed a gt28 rs , walbro 255 never installed my denso 550's. just put the ecu in that came with the engine to do a startup(will have jim wolf soon).started up ran idled kind of rough but when the electric fan would kick on it would start loping like crazy and die ,so i unhooked the maf big diff. it would surge a little but it idled pretty good and the fan did not affect it.well i left the cars side that night to sleep a little,got to it the next morning and it sound like a suburua when i started it so i pull the v.c and the rocker arm was off from the intake side of the #4 cylinder how does this happen sitting in the driveway at a idle??so i put the rocker back in place instlled both shims rocker arm locked in shims held 175 psi on that cyl. so back to trying to get this thing running right , well i never could get it tyo idle right with the maf so i give up for a couple of hours same thing wouldnt start so i pull the #4 spark plug and it is soaked i pull the v.c and is is the same thing exact same rocker arm. is there any way my fuel pump could be causing this,my #4 cylinder also has gas standing in it.BUT WHY WOULD THE ROCKER BE COMING OFF????????????

[jbart423]

any input would be great

[the converted]

It could have been broken from someone else over revving it, or you might have a bad lifter. What does the bottom side look like? and you can try bleeding the air out of the lifter to see if anything changes.