'95 Geo with black exhaust pipe

[senormechanico]

Originally Posted by Thymeclock

My gut feeling is that is the case.

However, short of that, a good diagnostician (I repair things other than cars for a living) looks for any clues mentioned, slight as they may be:



Maybe it's time to check that again. A previously seen and noted "burned valve" on a car that, down the road timewise, now has 160K might need a bit of attention to that detail.

I had the valve replaced 2 years ago (less than 5 k miles).
I checked the O2 sensor in a vise with a DVM and propane torch.
It works, almost 1.1v. with a flame on it and it drops to almost nothing in less than a second.

Thanks for the ideas.

[Domman56]

i diddn't see did you check your cat?

[senormechanico]

I don't have a way to check the catalytic converter. I wouldn't be surprised if it was bad, but we don't have emissions testing in our rural county.

The car is a '95, so it doesn't have a downstream O2 sensor. Only O2 sensor is in the exhaust manifold.

Is there a homebrew way to check the cat?

Thx.