only way to do it right is to lower the tank a little so you can see the lines.
sounds like either a pinched fuel or return line. blocked vent would also do the same, would create a vacuum in the tank starving the motor of fuel.
could try running it with the fuel cap off, venting the tank, but the end result is the same, lower the tank ON A JACK and fix the problem correctly...
1998 XJ on 37's.JK Rubi axles with chromo shafts and ctm's, 4:1 transfer case, etc etc etc.The Cherylkee....
2003 Range Rover HSE, 4.4 Quad Cam.
1998 Range Rover 4.6 HSE
2000 4.7 4WD WJ with a rebuilt motor.
4.3/700r4/new frame buildup (YJ)....
Years to gain the hands on experience, and offer it freely.
Minutes to gain the knowledge from the internet, and quote it just as freely.