Map Sensor and one other engine question

[jokershockey29]

Hey everyone, i have an 87, with a 350 with TBI. I have swapped map sensor, coolant temperature sensor swapped vacuum lines from map sensor. The tuck has no oxygen sensor because the previous owner installed headers and just cut the wire from the oxygen sensor and i can't seem to trace it so i can install a new one. On to the problem.. the vacuum line i installed is clear and i have noticed that there is gas in the line at the carb. any clues as to what would cause this or if its normal? I have no idea. Second problem is, the truck runs well, but after a bit of driving the engine begins to lope. if you let off the gas, no loping, if you hit the gas. no loping. It only happens when you are just cruising. I notice the rpm's jumping on the tack so i don't think its a trans problem but i really have no clue. Any help would really be really great. If you need more info just ask. Thanks guys
Brian.