if the gap of your spark plugs are set wrong will the car run right.?

Question

the car still run good but our fuel mileage has droped bad after we got a tune up. expensive plug where installed.

Answer 1

The gap is very important as it provides for a hotter spark and more efficient burning of fuel. Most spark plug gaps are now set at .060"

Answer 2

Maybe!... It depends on wether they set them too close , -or a little too far (the gaps). With the new high energy ignition systems, it will tolerateup to 10 thousanths or so too much gap, - without much change in "normal power", (now in racing at the high rpms, and high speeds it can make a big difference)! Change the deal the other way though, - and 10 thousanths can make the car run pretty poorly! And Runniung poorly, - makes the engine use more gas trying to go the way you want it to!-- A lot is wasted out the tailpipe!

Sparkplugs is about all that constitutes a tuneup, since the distributer has been "dropped", and sparkplugs are fired directly from individual coils!

The price of the plug has very little to do with how good the engine runs, - except that they will last a whole lot longer (hopefully)!

Answer 3

The gap would have to be extremely off to cause a noticeable change in gas mileage. Most platinum plugs come set to the average gap which is .060. Which really makes it hard for a mechanic to mess that up. Depending on the type of car and weather conditions in your area since the tune-up it could be anything from a large vacuum leak caused during the tune-up to a coincedence in weather change. Colder weather can cause pretty extreme changes in gas mileage and often makes it seem like something is wrong. If you need any more information feel free to message me. If I knew what kind of car it was I could be more precise as to what your problem may be. Hope this helps.

Answer 4

A.C. Delco #'s are more appropiate for what you ask. Most H.E.I. equipped Chevy small block V-8's call for .45 to .60 gaps. The .60 gap was for 350's built for the new "unleaded gas of '74-76' model years of all chevy design. Many other gm v-8 engines whent as far as .80 gaps with Hei distributors. I've experimented with this and found that a .55 gap is a good starting place if you are willing to change the heat ranges up and down through the seasons. A.c. plugs are the most reliable to tune through these variable seasons. I'm subject to alcohol fuel and allways measure the water level before making a change.

Answer 5

one thing to keep in mind and this is an old racing trick,you can open the sparkplug gap quite a lot as long as your coil and wires will handle the extra load.when your old spark plugs wear they open up which in turn can increase your fuel mileage ,then the new plugs are put in and your mileage drops.this is what may have happened,gm had settings up to 100 thou and i have seen fords running at the same setting.there are several good race tuning books that explain this.your expensive plugs may be giving you problems as well,i tried some of those 4 prong bosch plugs and my truck ran terrible

Answer 6

the spark plug gap is important as it determines the amount of heat created to ignite the fuel in your engine. depending on what car you drive it can be between .035 and .060. Under the hood there is a sticker..normally attatched to the hood and it will tell you the spark plug gap for your car. My experience...and I have worked on cars for over 30 yrs..expensive spark plugs doesn't always mean better...use OEM plugs....ie..GM you use AC plugs etc.

if you had it tuned up and the mileage went down...take it back and have them recheck things...or maybe you just decided to check mileage after it got tuned up.

Answer 7

Most plugs are pre-gapped to your vehicle's specs. and yes it will greatly affect your gas mileage since your car is probably not running with all cylinders properly-meaning if you have a v6 and one plug is bad, youre most like NOT burning the fuel on the cylinder with the bad plug. If you smell "raw" fuel, i'd take it back to the repair shop and demand satisfaction. Find your receipt and read...read...read.

Answer 8

i own a repair shop,and if the air gap is set wrong in them it will make it use gas like mad,and i wont run as good as it should run it can be off a few thousandth,s and it not hurt it that much,,but anything over that and its really going to use a lot of as gas,and you,ll notice a lack of power also on it,but you may have to re-set them to what they should be set on,to get it to run right,if the book calls for 32 on them set them at 30 it will make them last longer.and burn the gas better also ,and you,ll notice a little bit better in power also,,good luck,,i hope this help,s.

Answer 9

Dont think so .

Answer 10

no...
gap sets the firing..