I recently changed the spark plugs on a 1992 Civic DX, however I didn't quite use the right plugs. My girlfriend bought the plugs at the auto parts store, but instead of saying her car had the 1.5 she said 1.6 and purchased NKG plugs with the number ZFR5J-11, instead of what supposed to be in there which is ZFR5F-11. I had overlooked the one letter difference however, compared them to the old ones, gapped them and installed them without thinking.

Before I installed them the car was idling strangely. It would start fun, run at speed fine, but when idling it would rumble and go up and down while popping a bit. The car still idles strangely too. What I would like to know is if the plugs I put in can damage the car, and what else I can look for to explain the idle. The only other thing I did was changed the air filter which didn't do anything.

Thanks.

 

Well, on the NGK website, those plugs you installed are not listed as a type to be used in your vehicle. For the 1.6, yes, for the 1.5, no.

I'm thinking maybe you should take them out and put the right ones in.

As for rough idle, I'm having the same problem with my '04 civic. It can be a number of things, but I doubt its the plugs.

Someone here with better knowledge than I on the subject should make a suggestion for that.

 

Nah that wont make any difference. You're fine.

The idle problem existed before; existed after. What does that tell you?