A few months ago maybe over a year. I changed the Spark Plugs on my 1999 Honda Civic and the check engine light came on. The car was driving rough and when I stop on red light the car makes even a rougher sound. A few days later my car went back to normal and I turn off the check engine light by disconnecting the battery and reconnecting it. EARLIER TODAY I changed the Spark Plug Wire and I changed the Spark Plug and the check engine light came back on! I could drive the car, but when I push the brake to stop the car the engine shake and I could smell smoke a little. It does not drive smooth and the engine shakes more then before I changed the Spark Plug Wire and Spark Plug. Could anyone help me??

First, if you are going to try to diagnose and fix your car, you should really have an ECM reader to know what codes the car is throwing. Without the codes, you would be guessing.

I did find a general checklist to run through before you bring it into the dealer:


Spark Plug wires - OEM only for sure fix... aftermarket is a crap-shoot

Spark plugs - same as #1. This car is picky about the plugs you use.

Valve adjustment - every 30k recommended

Fuel Filter/s - for oil removal. CNG injectors are extremely sensitive to the slightest amounts of oil. If you're not changing them as recommended (and most don't) all it takes is using an old compressor that blows oil past the rings to ruin your day.

Fuel injectors - if all else checks out. Due to replacement price being the highest of previously mentioned items/services... test them first, replace them only after all other potential problems have been eliminated, unless they prove to be the problem right away. It's usually the injectors though.

Source (http://cngchat.com/forum/showthread.php?6645-99-civic-rough-idle)