07 Suburban rough idle P0304 code afm delete

[smokymtn65]

Pin Shear in cam, just going to pull this one and freshen it up..

 

[Geotrash]

Pin Shear in cam, just going to pull this one and freshen it up..

Sorry I missed your earlier post. This is the only thing I could think of that would do what you're describing all at once. I wonder how it sheared. Did the cam sprocket bolts back out?

 

[smokymtn65]

No its a single bolt cam. And was fully torqued still , 3ft cheater to loosen. I suspect a lifter failed and rotated maybe and shock loaded cam for lack of better description. I haven't pulled heads yet but will post the root cause if found.

 

[smokymtn65]

Well an update for this one, failed lifter on intake 4, jamed cam to shear pin and take out all exhaust valves and ex push rods. 220k almost no wear in cylinders, a hone, new pistons, cam , the works. Maybe by labor day.. lol

 

[Geotrash]

Well an update for this one, failed lifter on intake 4, jamed cam to shear pin and take out all exhaust valves and ex push rods. 220k almost no wear in cylinders, a hone, new pistons, cam , the works. Maybe by labor day.. lol

Check those lifter bores real close. If it jammed up enough to shear the cam pin, there could be other damage in there

 

[OklabyGodhoma]

I've read the whole thread and didn't see anywhere it was mentioned that the fuel filter was changed. I had a similar problem with my '07 Yukon 5.3 with hard start or 2 cranks to start and fuel smell from time to time. Chased it for a while and finally changed the fuel filter. Fuel smell went away almost immediately. I did not have any tune done nor do I have the advantage of the electronics test equip. Sometimes it's the basics that sneak up on us for what it's worth. Good luck!

 

[Geotrash]

I've read the whole thread and didn't see anywhere it was mentioned that the fuel filter was changed. I had a similar problem with my '07 Yukon 5.3 with hard start or 2 cranks to start and fuel smell from time to time. Chased it for a while and finally changed the fuel filter. Fuel smell went away almost immediately. I did not have any tune done nor do I have the advantage of the electronics test equip. Sometimes it's the basics that sneak up on us for what it's worth. Good luck!

There is no fuel filter on these trucks from the factory besides the one in the fuel tank as an integral part of the fuel pump. Is that the one that you mean?

 

[OklabyGodhoma]

ok

 

[smokymtn65]

Check those lifter bores real close. If it jammed up enough to shear the cam pin, there could be other damage in there

It is a bit rough right around the bottom of the failed one, it has been polished out. Fortunately not to bad

 

[smokymtn65]

My hard start was most definitely cause by a bad tune. Till lifter failed anyway. Lol