She idled great, until she didn't. . .

[Mike Quillici]

I have a 72 Chevy with a 350/350. I drive her on and off, but right now my daily driver is in the shop, so I'm driving my truck to work every day. Today, I was running some errands at lunch, and she was running just fine. I got on the freeway for about 3 minutes, and when i got off, I noticed she was idling really rough, and at low rpms (~500 in gear).

I'm wondering what may have happened in such a short time to cause such a change. Oil in engine and tranny are good. Power steering was very low (off the stick), but I added some. Distributor is locked down tight, so I don't think it's a timing issue. Pulling the PCV hose from the front of the carb really causes it to run rough, as would be expected, so I don't think it's a massive vacuum leak.

When I get home tonight, I will check to see what my idle vacuum is, and spray some carb cleaner in the carb. Does anyone else have any ideas? She seems to run fine off of idle, although the transition is a little sudden.

Thanks,

Mike