1983 5.0 liter with computer-controlled carburator.

For some time, the car has idled rough.
Checked timing, as I thought that the chain might have slipped a tooth. Timing is where I left it after doing the work mentioned below.
Checked vacuum. Very high at 25" Hg.
Changed O2 sensor.
Pulled plugs. VERY LEAN. All plugs have snow-white porcelain, with just a touch of tan residue.

If the intake gaskets were leaking, the plugs would be a variety of colors. I replaced them and the carb gasket last fall, as I was loosing anti-freeze.

Can I have a vacuum leak, in spite of the high idle reading?
Is the repair simple and obvious?

What do you think?

Thank you,

Seth

 

If the timing chain is known to be bad, change it. A streched or jumped chain will cause all sorts of problems and headaches for you.

 

The chain does not appear to be an issue. I simply needed to check whether the timing was where I had left it,; because when you replace the intake manifold gasket(s), the distributor comes out with the manifold.

Thanks,

Seth