I've got an '84 Vanagon GL that I can't get to pass smog because it won't
idle between 2250 and 2750 RPM. It will idle lower, and if it idles a bit
quicker, something in the engine shuts down the idle speed after just a few
seconds. It will idle much faster, but too fast for the smog test.

Other information:
100K on car
The OxS light is on.
30,000 mile service done 6 months ago at Bug & Hare in SF.
Muffler probably needs replacing. Last piece of tail pipe fell off.
Transmission may be ready to fail. It had trouble engaging in drive when
first started. I.e., sometimes it took several minutes to engage in drive,
and then a terrible thunk. I was ready to junk the car, and then I put in
TransX and the problem immediately went away.
Supposedly, there are some cracks in the heads. I.e., the compression is
low. Very little coolant is lost.
There is a leak in the gas tank when completely full.,

I think that the least to diagnose this problem would be $125.

However, the car seems to drive just fine right now.

Is it worth it to pursue fixing this beast. I like the car, but I think that
it may be ready for donation to my local charity. I already bought a new
minivan, but I lik e having the old one for taking to the beach with my
sandy/salty windsurfing gear.

Has anybody had a similar problem with passing smog? Are there any quick and
cheap fixes?

Thanks for any information.

Justin