Questions and Answers

Honda Won't Idle Correctly Q. I'm praying that you can help me with this because nobody else can. I have a 1998 Honda Civic EX. About one year ago I installed a cold air intake, apex world sport exhaust, and DC 4 in to 1 headers. Ever since I had the intake and exhaust put on the car, it has idled rough. The car idles at about 400 to 500 rpm and feels really rough.

But when I turn the headlights on, the idle shoots up to 850-900 rpm and feels smooth. Also I have noticed that whenever I step on the brakes or roll down the window (whenever there is a power load) the idle will shoot down to about 150 rpm and stay there until I step off of the brakes or the window finishes rolling down. I have noticed that the car only idles rough between 300-650 rpm, anything above or below that it feels smooth.

I've been to the Honda dealership twice and they can't figure it out. The spark plugs, wires, cap, rotor have all been changed, the valves were adjusted and none of this has helped. Please help!!!!!!

1998 Honda Civic EX
5 speed manual
1.6 liter VTEC
96,000 miles
A/C,P/S

Thank you,
Mike B.

A. It would seem to me you told me what the problem is. You altered the engines operating parameters and moved it outside what the computer can control. I'm surprised the Dealer didn't tell you this. If there are no vacuum leaks or engine controls disconnected you have two options. Restore the original intake and exhaust or live with it.

Additional Information provided courtesy of ALLDATA