05 Z71 5.3 not flex fuel random stalling

[RonnieB2nd]

I replaced all plug wires, plugs, MAP, MAF and it ran better. But the stalling came back today in a big way. I also used ethanol gas treatment and fuel dry. When its running right, its smooth as glass then out of nowhere rough idle and stalling. No codes or check engine light. Fuel pressure is 60'ish. Too random to be cad converter and has plenty of power. Im thinking of replacing random sensors at this point. I have a temperature sensor ready to go. I guess a crank sensor could not hurt. Its too random to be the crank key and my voltage is really good. Anybody ever hear of this issue? My next move after sensors is dropping the fuel tank or pumping it out. Any help would be appreciated more than you know. Thank you.ps I thought vacuum leak but again it's random. Ive never seen anything like this. Im completely lost

 

[RonnieB2nd]

[Coukd the throttle body cause this QUOTE? I also cleaned it really well QUOTE="RonnieB2nd, post: 1574073, member: 84624"]I replaced all plug wires, plugs, MAP, MAF and it ran better. But the stalling came back today in a big way. I also used ethanol gas treatment and fuel dry. When its running right, its smooth as glass then out of nowhere rough idle and stalling. No codes or check engine light. Fuel pressure is 60'ish. Too random to be cad converter and has plenty of power. Im thinking of replacing random sensors at this point. I have a temperature sensor ready to go. I guess a crank sensor could not hurt. Its too random to be the crank key and my voltage is really good. Anybody ever hear of this issue? My next move after sensors is dropping the fuel tank or pumping it out. Any help would be appreciated more than you know. Thank you.ps I thought vacuum leak but again it's random. Ive never seen anything like this. Im completely lost[/QUOTE]

 

[Fless]

After it stalls can you start it right away, and does it run okay when you do?

What do your long term and short term fuel trims look like?

 

[OR VietVet]

You said fuel pressure is 60'ish. Have you attached a fuel gauge and watched as driving and see if when it stalls it loses that pressure? On my 05 Z71 the only rough idle/shudder problem I had and wopuld have died at stops if I did not go to neutral and rev the engine a bit. It was the Bank 1 sensor 1 causing that. It was also intermittent.

 

[afpj]

Although not generally a fan of the parts cannon method, aside from checking the fuel pressures and O2 sensor readings already mentioned , consider camshaft position sensor . Btw, what is ethanol gas treatment for? Are you using crappy gas?