Hey y'all! Last May I bought a 2000 dx civic that seemed in pretty good shape. Only 97k miles on it, and the only problem both my mechanic and I could find was that the o2 sensor was out (It was throwing the code) and the brakes and tires needed to be redone because it had been sitting around for a while.

Fast forward to January I finally get around to changing the o2 sensor, and I find out that my exhaust manifold has that infamous crack. I replace that manifold with one from ATP, and all of the sudden I have 3 new CEL codes. I have P0135, P0155, and P0505.

I figured those codes are what could be causing my rough idling that I had been experiencing for a while, but then my CEL goes off. The light still works when I turn the battery on, but when I'm driving it is no longer on, yet I'm still having rough idle problems, and my car hiccups when I drive. Along with all that she's started to get quite a bit of engine pinging, especially when I'm accelerating past 30 mph.

So I guess I'm wondering if any of y'all that have more experience can diagnose what's happening and how to fix it, because it feels like each time I try to fix something another thing goes wrong .
(This is going to be my thread that I come back to when new problems arise that way I don't have to clog up the boards with new threads)

 

Tune up time. Double-check timing time. Cleaning IAC time yay!

 

The IAC valve is located underneath the air filter, correct?

 

I think it was mounted on the back side of my intake manifold on my old d series. There's 2 coolant lines hooked up to it,a sensor, and 2 12mm bolts. Then I just cleaned it with kitchen cleaning supplies lol. It was called simple green. Raised my rough 300 rpm to a smooth 800.

 

That would be on a Y8 or a Y5.

The IACV on a D16Y7 is under the air filter box in front of the throttle body. If you need a replacement I just swapped out my top end and am parting out my Y7 intake.

 

Hey y'all, thanks for the info! I did do a tune up, air/oil filters, new o2 sensors and oil, new spark plugs and will do the fuel filter when I can get an impact wrench to get the bolt off.

That helped a little bit, but one problem seems to be getting worse. Whenever I am going over 40 mph (Usually happens when accelerating or at a steady pace) my car 'hiccups' and I can hear a 'squeak' right when it hiccups, I think it's coming from engine bay somewhere. Is this more than likely a timing belt issue? No CEL on right ow.

 

Haha, just remembered I already replaced my timing belt and tensioner back in November.... So now I don't really now what this could be.