My 94 Blazer s10 is a v6 Vortec 4x4~
Issue:
When the engine is cold there is a vibration coming from firewall top area of engine. The engine will periodically bog down/ then the CPU will dump fuel into the engine and the RPM's go up for awhile then it bogs down again. Sometimes it will stall before cpu can dump fuel on it, the issue is getting worse and worse with stalls becoming more frequent. I can avoid stall by hitting accelarator. Once all the way warm and driven on normal honey do errands for the day it runs perfectly, vibration even gone. No idiot lights yet;
Current troubleshooting done
I was almost certain that the vibration was cap and rotor. I could feel vibaration strongest when I put hand on cap while idle. Replaced cap and rotor to no avail. Will be replacing wires and plugs this week. However I am by no means a rich man and diagnosing this problem by replacing ignition system a piece at a time then moving onto fuel delivery and air control systems will break a fool.
