just throwing it out there for all you lsx gurus. hopefully someone can help.
ive got a thorn in my side at work. 06 chevy pickup with a 4.8l has constant misfire on cyl 4 at idle. it has about 80k miles and is used by a company as a work truck. the truck runs great off idle, and the cylinder doesnt seem to be "dead". just watching my scan tool it misfires about once every 2 seconds.
anyway i pull the plug and it's worn. replaced plugs and the misfire is there still. switch coil and wire with a different cyl, no change. the injector ohmed within spec. sprayed for vacuum leaks, found a small leak on the intake gasket. i replaced gaskets and injector o-rings, along with moving cyl 4 injector to a different cylinder just for shits.....everything got put back together and torqued to spec and cylinder 4 is still missing away.
the engine sounds strong (no knocks or funny noises), fuel trims are +/-4 on both banks. O2 readings look good. i cleaned the MAF then unplugged it. i went as far as injecting smoke into the vac lines to see if the plenum itself was leaking, but didnt see anything. i'm stumped and not really sure where to go next. soooo any help would be greatly appreciated.
ive got a thorn in my side at work. 06 chevy pickup with a 4.8l has constant misfire on cyl 4 at idle. it has about 80k miles and is used by a company as a work truck. the truck runs great off idle, and the cylinder doesnt seem to be "dead". just watching my scan tool it misfires about once every 2 seconds.
anyway i pull the plug and it's worn. replaced plugs and the misfire is there still. switch coil and wire with a different cyl, no change. the injector ohmed within spec. sprayed for vacuum leaks, found a small leak on the intake gasket. i replaced gaskets and injector o-rings, along with moving cyl 4 injector to a different cylinder just for shits.....everything got put back together and torqued to spec and cylinder 4 is still missing away.
the engine sounds strong (no knocks or funny noises), fuel trims are +/-4 on both banks. O2 readings look good. i cleaned the MAF then unplugged it. i went as far as injecting smoke into the vac lines to see if the plenum itself was leaking, but didnt see anything. i'm stumped and not really sure where to go next. soooo any help would be greatly appreciated.