deanq4

OK, I have a 97 HX, pretty much 100% stock or equivalent parts on it. About 6 months back I noticed my gas was slipping a little so I thought I would change my plugs (it was time to anyways) The plugs were a little dark for my taste so I threw in some Denso plugs (the ones it recommended on the hood of the car) about 3-4 weeks later I noticed things were not acting right, so I pulled the plugs and they were pretty dark for being new plugs.

I took it to my mechanic since I thought maybe it was something to do with fuel injection (I don't do things with fuel injection). He tested all the sensors and drove it up and down the road with no problems, suggested that maybe it was the O2 sensor, but that it was testing ok, but sometimes they are fickle like that. I have not wanted to invest the $100-300 for an o2 sensor till I was almost certain that is what it was. He noticed the plug wires were old and may need changed, so I changed those, and got NGK plugs to put in.

After I changed the wires and the plugs (cap and rotor too)I noticed the car began to run a little rough when it was idling, it would be fine, the try to stall a little, then be fine dropping from say 700 down to 400 really quickly then back. I think it may be that I got Bosch lifetime wires, but can not be sure… have not tried exchanging them yet.

I have began to notice another “symptom” that I am not sure has anything to do with this, but have noticed it goes away when I changed to fresh plugs, then comes back within 1000-2000 miles or so. It is not a real problem, but more an annoyance. When traveling for a while at 60-65 MPH (2200 - 2700 RPM in 5th) it feels like it will cut out once in a while, like it will be trying to stall for a split second. Most passengers just think I am taking my foot of the gas for a split second. I have read that the HX runs very lean under 2500 RPM (more so that other V-tech’s) and wondered if this has something to do with that, it gets to be annoying when I drive about 150 miles each weekend and it does it 75-80% of the way. It doesn’t do this if I stay around 60 MPH, but that is too slow, and at 70 it is ok too, but I can’t afford tickets (more than 10 over), at least that is what it seems.

Thanks for any advice, and hopefully some helpful tips.

INFO: Car has 97000 miles and has the original o2 still. Fuel filter is less than 15K old and plugs are now about 5-10K old. I run an additive injection cleaner ever 5 tanks (or so) and try to run mid-grade gas (89 I think) since it is about a 10 to 1 ratio. I do get 38-40 MPG, but used to get 40-44 MPG.

1995Ex_Sedan

You should really change your Distributor cap and rotor as well. And, its Vtec.

dpkelly

I'd check also your tps (throttle position sensor) maybe clean out the IACV. While your at it, check the compression, and timing, valve clearances. Too much injection cleaner can clog the fuel filter. I'd get some injectors from a junk yard to put in your car while you take yours out and get them professionally cleaned. Make sure you get the O-ring kit from Honda otherwise you'll get gas leaks . What about your PCV valve? Be sure to get a Honda one. Start with the cheapest thing and move up.

deanq4

Thanks, I'll look into those things and see what I can do. I know he checked the TPS, since I asked for that due to last car have really bad issues with it (not a Honda)

I did do the Cap and rotor with the change of the wires.

I was told that Honda's had a self-correcting Timing mechanism.... maybe that is not true?

Thanks Guys