I have a 1995 Blazer 4x4 4-door, VIN code W 4.3L V6, with 209K miles on it. Yesterday, I replaced the spark plugs, plug wires, distributor cap (with side towers), and rotor; everything's new AC Delco parts except the plugs, which are E3 Diamondfires. Now it's running rough and smelling rich, like a cylinder isn't firing. It gave me a MIL (service engine soon light), too, flashing on the dash like something's wrong (duh!).

I pulled out my AutoXray EzScan 6000 to try to pull the code so I could see what was wrong. My Blazer's got an OBD-II computer in it (yellow cable from the AutoXray, set to 1996 year model, communicates; set to 1995, with either the yellow or blue cables, says it's not communicating). I ran the scan. It told me that the MIL is on, but that there are no codes stored.

I reseated all the connections at the spark plugs, and wiggled the wires, but the condition doesn't change. How do I go about finding out what's wrong? Preferably without burning the hell out of my hand on the exhaust manifold?

 

If you smell it running rich, it would be my guess that the plug wires are crossed somewhere and the cylinders are not firing correctly and the un-ignited fuel is being sent out the exhaust...double check and recheck the wires at the cap and the plugs

 

I thought I'd double-checked, but checked again, and sure enough, the wires to 4 and 6 were reversed at the distributor. Swapped them, things are good. Still wish I knew why I couldn't pull the codes, though.

 

glad you found it, it could be because it was coming up as a mis-fire and it just didn't know what code to put...