[wildcat47]

new to this forum but not to auto forums. hello to all and thanks in advance for your help. i have a 91 lumina with a 3.1, 90k miles. on way to work last week engine was lagging immediately on startup and all the way to work, i could hold 70-80 mph as long as i was on flat ground or downhill and can even acclerate slightly,,,,but car will lag if uphill or med acceleration... if i kicked the pedal hard, engine will go into passing gear and acceleration is fine with no noticible lagging.
i have replaced plugs, wires, fuel filter and ran a quart of seafoam thru engine with no real improvement. i did notice that while i was changing the plugs there was a small bit of fuel accumulation at the throttle body [ noticed it when i took the intake tube off to tilt the engine forwared.
temp sending unit? fuel injector/s? o2 sensor? fuel pressure?