Rough Run

[pound41]

Have you done a compression test. I had my 71 blazer that I have owned forever start doing similar things. Ran good but had a hic up in it. Had about a 130k on it did a compression test. 7 cylinders were great one very weak. Bought a 1970 blazer that ran good just felt like it needed a tune up. Tuned it up it became more noticeable. Same situation. Hopefully thats not your cause. Good Luck

[elkniks]

This may start an argument, but anywho do not connect you distributor vac advance to the timed vac port on your carb, that is for smog stuff only. Connect to full manifold vacuum.

[geunther]

Originally Posted by elkniks

This may start an argument, but anywho do not connect you distributor vac advance to the timed vac port on your carb, that is for smog stuff only. Connect to full manifold vacuum.

No argument, I know there are two schools of thought. I hook it there because that was the original place from GM. Looking over the VA it looks fine, as far as I can tell.

Originally Posted by pound41

Have you done a compression test.

I did. My tester would not lock at the high point but I observed the needle go to roughly 120 for each cylinder.

[geunther]

Just wanted to close out this post and thank everyone for their input.

The truck is running fine, but to be honest I still don't know what the problem was. I disassembled the distributor, cleaned, shimmed it to about .015 to .020 clearance, new points, new condenser, new advance, and reinstalled.

There was some crusty grease on the lobes of the dist except where the points ride on the shaft. Potentially as the dist shaft would ride up and down, the crusty grease affected the opening of the points. Or the condenser was intermittently bad. I dunno.

Regardless, up and running. Thanks.

[Redline novdog]

Thanks for the closure don't have a whole lot of that here.God luck and Happy driving!