1986 Coupe Strange Idle

[Andrew Finney <afinney@tamsconsultants.com>]

My brother's 1986 Coupe has an idle problem. First, I
discovered that someone had replaced the OX sensor with a
non-heated version. If the car is idling, it suddenly speeds up
and then slowly returns to normal idle and it will keep doing
this is cycles. If I disconnect the OX sensor it idles at a
constant speed. It sounds to me like it's time to replace the
OX sensor with the correct part. Anyone have any thoughts.

Also he has an insane amount of noise coming from the
mechanical vacuum pump. Can you just pull it and clean it, or
is the fix more drastic?

Thanks,

Andrew Finney
1983 UrQ.