My 91 Chevy c1500 4.3 v6 had a rough idle then after accidentally revving in neutral won't idle. It will stall out at idle, I've replaced the IAC, PCV, EGR, MAP, ECU, TPS, TB gasket, and all to no avail. I've had the minimum air raised so it wouldnt stall on me everyday. Then after someone slashed all my tires (and being broke from all these replacement parts) it sat for a month and I only ran it once for a short period of time. Now it won't idle and immediately wants to stall. With minimum air adjusted extremely high it still stalls. I also noticed the vaccum to my brake booster is weak and doesnt cause my engine to Rev high like it usually does when it's disconnected. I've probably replaced more parts I can't think know of and now I have no idea what to do. Any thoughts?

 

Its going to sound kinda stupid, but whens the last time u did a full tune up? Bad fuel filters can make a rough idle and can also contribute to the stalling. Also a bad cap and rotor could account for that aswell. I have a 90 k1500 and it ran pretty rough with shakes in the engine when idling. I replaced the cap and rotor today and the rough idle and shakes ceased.