I have a 91 Chevy Astro van with 15x,xxx miles. It idles very rough and drives extremely poorly at around 40mph, and, overall, seems to lack a bit of power.
A compression test was performed on the vehicle. One of the cylinders read approximately 70psi, with another around 120psi. Obviously, these readings indicate a problem of some form.
However, my check engine light also comes on periodically. The van is throwing code 13 (open oxygen circuit) and code 45 (rich exhaust). I realize the O2 sensor itself could just be faulty, but this would not explain the low compression, nor, likely, the performance issues.
As such, I am curious if the reverse could be true; is there anything that results in low compression (burnt valve, head gasket problems) that would also result in these codes being thrown? Also, please note, the light only comes on sporadically; it is not consistent. In general, given this set of symptoms, what might be a likely cause of the van's performance problems?