I just changed my plugs and wires in my 96 Nissan 200 sx 1.9 l SE and went from 33 mpg to about 25 . My gas needle hardly moves when I fill up before plug and wire change -using same gas station and same 97 grade ,just went 30 miles and the needle is already moving ? What can be causing this - the spark plugs that were taken out were fried ? do I need a new air filter -have a big cone air filter with cold air intake - could it be a dirty air filter with new plugs and wires ?
This makes no sense- new plugs , new wires= better MPG ????
Drop in MPG after changing spark plugs?
Did you use bosch brand plugs? Or any of the fancy 2, or 4 ground strap plugs? If so thats your prob.
Did you check and gap the new plugs to OEM spec? Plugs clam to be pre gapped but they aint.. You must always check and gap them.
Drop in MPG after changing spark plugs?
Well, according to the ancient law of fingerprints, whatever you did last is the cause of the problem now.
Are the new plugs exactly correct? Right heat range? Correctly gapped? Resistor or not?
And are the wires good? If they are resistance wires to get rid of radio interference, they could be a problem.
You are right. Things should have gotten better and what you did last dented something.
There's no way the spark plugs contributed to your 8 mpg economy loss. Perhaps when you were changing the spark plug wires you bumped the distributor a little, or knocked a sensor wire or vacuum hose loose.
Sounds as if you got the wrong brand plugs in the car. Did you get them from autozone, that will be your answer.
