Got an 87 IROC with a 305 TPI. Car misses at idle and throughout RPM range. At highway speed it lugs real bad in overdive while you are accelerating. I've changed cap, rotor, wires, plugs..etc. The dead cylinder is #2. All cylinders have good pressure, fuel and spark. I was told by a local garage that it was definaltely a worn valve guide causing the problem. The plug carbon fouls quickly, but there is no oil on it. Anyone else have this problem and found a valve guide was causing it?

 

It could be as simple as a clogging fuel filter or a dying fuel pump or as sserious as you described. I would check the fuel system. GM fuel systems are not the most reliable thing out there.

 

The pump and filter are good, the fuel pressure tests fine at the fuel rail and the injector is working properly, still has a dead cylinder.

 

It would be a good idea to run a compression check on your #2 and on all your cylinders just to verify what is going on. I would check your rocker arms and see if they are on tight or if there is chatter/dead lifter. When the lifter (hydrolic roller for my application) went bad on my bird it made a squeeking noise which indicated it was not getting lubricated.
Another place to check would be your air sensor. THis is located on your exhaust driver's side and lookes like a spark plug thats screwed into afitting. I have experienced this go bad on my bird and it helped significantly once I replaced it please check it before you buy a new one. Have your mechanic test your emitions to see if the car is running lean or rich. These extremes would indicate a faulty air sensor.

 

If you are sure it's only one cylinder, look for collapsed lifter, bad rings (do a cylinder pressure test ) bent pushrod, head gasket or as mentioined bad valve guide.

 

All cylinders tested ok for pressure so I'm leaning towards the lifter/valve spring/valve guide idea. Thanks for all of your input on this!..it's people willing to help other people that continue to make this a great board and a great resource.