I have a slight miss at idle and was doing a seafoam treatment today and noticed that i had smoke and liquid comming from the joint between the manifold and the down pipe on the drivers side. Can anyone tell me if there is a gasket between the two parts? or do i just need to tighten it up? any link to the missfire?

Thanks

94 5.8L

 

not sure on these trucks but on newer chevys there is a little rubber like piece that goes in between there. we call it a donut. just take a wrench and a socket wrench and tighten it. that'll fix the leak. it'll make the truck sound better too. as for the misfire that could be a lot of things. not the exhaust leak tho. start by replacing your spark plugs, then your wires, then your distributor cap and rotor, then make sure your coil is outputting correctly, then check for vacuum leaks, the list goes on and on. but most of the time its one of the first things i listed

 

There's no gasket or doughnut. It's just a flared tube end and a conical seat. It should seal up by tightening the fasteners but you may have to loosen the other side and re-tighten both

 

No gasket. If it has been loose for a long time, it may have worn a groove into the manifold, preventing it from ever sealing again. Loosen the OTHER side, then remove the leaking side & inspect. Use penetrating oil before disassembly, and anti-seize lube before reassembly. If you have to replace a manifold, there's no gasket on them, either. Read these captions:

 

Thanks! No worn groove so all is well. Now if i can only figure out this miss. I'm at a loss. It started some time after i changed the plugs, wires, cap and rotor. I have checked the wire routing and looked at night to see any arcing.... new MSD coil timing is good at 10 btdc. a bad plug? Is there any way to pin point the cylinder?

 

The common method to find a miss is to let the engine idle & use insulated (or grounded) pliers to pull each plug wire off, then reattach. If you find one that DOESN'T cause the idle to degrade, then it wasn't working before, so it must be misfiring. But check them all - don't stop with the first one that seems bad.