those cars used to eat fuel injectors for lunch and dinner.
if you can unplug the injector harness and check to see if one batch of injectors ohms out differently from the other and you will probably find a shorted-out fuel injector
Yup, spendy buggers too if I recall. I have one or two good ones that I could part with if that's what it ends up being. My 3.1 days are over.
1998 Grand Prix GTP aka The Family Sedan
CAI, 1.8 rockers, U-bend delete, 3.4 pulley, tuned by me
1999 Turbo Grand Prix
L36 turbo build in progress