I have a 95 Silverado with the 350 tbi. I'm getting a misfire but no light. It's fairly significant while cruising at highway speeds 60mph(1600/1700rpms) and under a load it isn't as noticeable. I have a slight intake manifold leak also but not sure that'd have Anything to do with it. Wondering what I should start with? Thanks

 

No one??

 

I can't make out what your talking about. Misfire at highway speeds?
Slight intake manifold?

 

Slight intake manifold leak. And highway speeds is when it's most notable but does it at all speeds.

 

Maybe there is no fault code stored in the Power Control Module.
Maybe you should diagnose this by monitoring knock sensor data...

 

If you have a known vacuum leak I'd certainly start there. More often vacuum leaks will cause high idle and surges though.

Several things can cause a miss. Catalytic converter, fuel delivery, spark/timing. If the truck is due for a tune up go ahead and do it. It doesn't cost much to replace the fuel filter, plugs,wires, rotor,cap, and coil. This will eliminate alot possible causes. Pull the distributor and check the gear for wear.