Truck Repair: truck problem, gmc sonoma, vacuum leak

Question
are truck 1991 gmc sonoma 4.3 is  making a funny noise even when waiting to cross a street sounds weird like spit or trying to bog out scarry sound.
my husb changed spark plugs, and  he also changed gas filter,distributaar cap , roaters,brakes  it use to smoke  bad then we used smoke treatment and it  stopped ,and go through oil .. we dont know whats going on it also seems draggy  to  me  please help

Answer
Hello MK,
Might check the exhaust system to see if the catalytic converter is plugged. If it was running bad for a long time, that is sure a possibility. A plugged exhaust will make it act like that.

A vacuum leak is another thing that will make it run terribly.

Van