I have a 87' jeep YJ 4.2 258 thats making a "popping" or backfiring sound that is I can hear the loudest when I take the air cleaner cover off...seems to be coming from the carb....I took it for a drive around the block but it got louder the more I accelerated it was hesitating, bearly got it back up into the driveway. Im praying its not a job I can't do...but any help would be appreciated!