Home » Ignition Systems » Do Wider Spark Plugs Gaps Increase Gas Mileage Do Wider Spark Plugs Gaps Increase Gas Mileage Does increasing spark plug gap above factory specs increase gas mileage? If so, what amount beyond factory on average gets the best improvement in mileage? Tags:Factory Specs, Gas Mileage, mileage, Spark Plug, Spark Plug Gap Related Questions VW 02 TDI Glow Plug Stuck Inside Thread Gone How To Pull Out Hi, THANKS. Zach, you’re good very good! Thanks. Electrical Tape On Distributor Wires Can you put electrical tape over wires that lost parts of the rubber covering them, that connect to the distributor??? or will the tape melt or something? On a Answers for The Question itsthewill no, doesn’t help gremlingts no, not wider gaps necessarily , they are just there for high energy systems versus the older points-based system, which had lower voltage coils and couldn’t jump the bigger gap. If you get a MSD unit ( Multiple Spark discharge ), you can have your plugs fire 2-3 times each stroke, which will help reduce mis-fires, and WILL improve gas mileage a little bit. They can be costly, and might require computer chip reprogramming in your car/truck, but it is one of the few spark changers which WILL help a little. Another change is positioning the spark plug so that the finger which extends over the center electrode is not blocking the intake valve discharge. I don’t know how it is possible to line them all up, depending on the threads, but hot rodders have marked them and then shimmed them so that the rear of the side finger won’t block the air and gas flow from the intake valve, which gives it a clear shot at the spark. A VERY picky point, but I suppose it could affect gas mileage on a few cylinders that way. And so minor, but when you need 1-2 extra HP out of a 1,000 HP mega-motor, I guess any small advantage is STILL an advantage. – The Gremlin Guy – mdk68gto a gap that is wider than spec can lead to a misfire or premature failure in the ignition system. Incoming search terms: Wider Spark Plug Gap,Wide Sparkplug Gap Vs Narrow,Spark Plug Gap Sbc Mpg,Bigger Spark For Wider Plug Gap,Vahow To Determan Distributor Misfire,What Does A Bigger Spark Plug Gap Do,What Does Widening The Gap On A Spark Plug Do,What Dose A Wider Spark Plug Gap Do,Will A Larger Spark Plug Gap Hurt Anything,The Wider The Plug Gap Without Missing The Better Right ?