will it harm to use a bottle of that type of fuel tank additive - the car has 182,000 and is hard starting, stalls at idle, getting poor mpg- no stall id keep idle at 2000 !! - have replaced primary fuel filter -suspect it wss original - it was very cloggd green stuff in filter paper!!- and got a secondary filter today, recently replaced wires and plugs- also had front crankseal leak- got it replaced for $100- that caused quite bit oil soak in front area--