I have a 2000 s10 4.3 it has random misfire but reads that cylinders 4 & 6 are misfiring the hardest I’ve changed ALOT already from plugs wires distributor fuel injectors fuel filter/pump crank shaft egr but trust still blinks and misfires going more than 30 sounds like I have a vacuum leak my question is the vacuum leak could cause the p0300 but would it be making those 2 cylinders misfire the most? Also any recommendations on what to do been trying to get this misfire for 2 months now and still don’t have my truck back lol huge fan!! Love the videos!! Truck is about to roll over 200k miles and is automatic
Get a scan tool and find out. Any tool that has live data should give you a pretty good idea on how it's running.
If you've never changed any of the vacuum hoses in your car, after 23 years, those are probably getting close to dry rotting.
sounds like I have a vacuum leak my question is the vacuum leak could cause the p0300 but would it be making those 2 cylinders misfire the most?
yes. Vacuum leaks absolutely do cause misfiring. And these engines are notorious for failed intake gaskets causing vacuum leaks. Particularly in the rear cylinders of the engine where it gets the hottest.
If you spray a bit of starting fluid or propane around the back of the intake manifold, you might hear the engine speed up. Or use a smoke tester as JS said in case it's just some rotten hoses.
