Weird miss at idle

[scottsdale86]

Truck is a 1986 scottsdale with 350 and non CCC quadrajet. I went up some fire trails this weekend and it ran great as it has been then yesterday i fire it up to go to work and it was idling really low and missing. Never died but sounded like it wanted too. Choke is fine and working. At freeway speeds or at a stop light there is no hesitation or stumbling it goes as it did before it just idles like ****. Rough, low idle speed etc. I am thinking maybe something is loose since the trail was rather bumpy but i cant for the life of me diagnose it. The plug wires aren't arching, it just had a tune up two weeks ago which included new plugs, cap, rotor, fuel pump etc. What would my symptoms be if there was a vacuum leak? Is there any other fuel filters other than the tiny element in the carb inlet? Any help would be appreciated

 

[diesel4me]

Could well be a vacuum leak--try spraying carb cleaner at all the hose connections at the carb,and the base gasket,brake booster hose connection,PVC valve,and ensure no hoses are disconnected or cracked at the nipples...the truck will have a "sock" in the gas tank in addition to the fuel filter in the carb,no others unless one was put on by someone along the line..seeing it accelerates OK and will maintain highway speeds I'd guess its not a fuel delivery problem...more likely a vaccuum leak,or maybe your float is sinking in the carb or some dirt is letting gas leak by the needle & seat and flood it slightly...

 

[scottsdale86]

I'm thinking float because of the very rought terrain i went through on sunday. Possibly causing the float to get hung up on something or a piece or dirt. Its just weird because it started out of nowhere. I have had zero mechanical engine problems with this truck so i guess i was due for one. I'll double check the plug wires and that they are making good "click" on the cap and plugs and maybe pull the top off the carb.