off topic, sorry. my truck, 78 toyota 20r motor/4speed.
originally: cough, wheeze and backfire OUT OF TAILPIPE going up a certain hill at exactly the same spot every morning Stunbled it's way to top of hill, ran fine the rest of the day. BUT NOW I am noticing it's becoming more finicky and doing this more often. My guess is distributor is not advancing correctly or there's a fuel problem,: weak pump?, dirty tank?, fuel filter? carb in need of serious rebuild??? It seems like if it was advance why would it be getting worse? Maybe fuel system is slowly plugging up? But why the backfire? Remember : this is tailpipe backfire , it doesnt seems like it is thru carb.