melpod87

I have an 86 manual transmission civic wagon. Recently it started losing a lot of power especially once I get above 2nd gear. Once I shift to third or fourth it loses power and if I don't downshift the engine starts to "stumble". Also, over the last couple months it's been having ideling issues (idling too high or sometimes stalling). My mechanic said it was probably a carburetion problem and he thought the engine was running lean (hot) based on the condition of my spark plugs. I just spent the last 2 days removing and rebuilding the carburetor. It's back in the car now but but I'm still having the same problem

Any other suggestions as to what might be causing this? I'm not sure what to try next.

- Mel

ezone

You sound like it is either starving for fuel or it can't breathe.

Do an exhaust backpressure check. Disconnect the exhaust in front of the cat if you think it is clogged, then give it a quick drive.
Wait...Crap, that's right at the manifold.
Um, try removing the O2 sensor and give it a drive. If it goes ANY faster then you may be on the right track with clogged exhaust. You can put a pressure gauge in the hole from the O2 sensor to measure backpressure too.

Check fuel filter/fuel pump.

Each acts a little different, but results are somewhat similar when clogged.



Very hard to tell from your description. Could be other stuff too, but that is what I thought of first.

melpod87

Thanks for those suggestions. I actually went ahead and replaced my fuel filter but that didn't seem to improve things. Next free afternoon I have I'll disconnect the O2 sensor and see if that changes anything.

iim1rmg

Please post what happens with the O2 sensor.

I have an '87 Civic with similar symptoms but only in the top two gears and only when under load, like trying to accelerate uphill.

I've addressed all the "usual suspects" and now I am down to the unusual.

I'm going to replace the O2 sensor and see if that changes anything. In my case, I don't suspect exhaust backpressure issues as it runs great until it starts to stumble, and letting off the gas and coasting for about three seconds clears the problem once it starts stumbling and missing.

I am hoping its the O2 sensor, but if not, my next guess would be one of the many vacuum valves that are no longer available.