restart and runs different?

[corelokt]

Sometimes my engine sounds loose, like lifter noise, and runs rough. If I shut it off and restart it, it sometimes will then sound like it is brand new and spot on. Any ideas what's up?

 

[Triple C]

We talking 6.2 NA?

 

[corelokt]

Yes.

 

[Triple C]

I would suspect the fuel filter. If there is come crud on the filter, killing the engine will allow the crud to drop to the bottom and sometimes stay there at restart. Just a thought, but I would suggest a change of filter and see if that handles it. Good luck.

 

[2deuce]

When it is running rough how does the tailpipe look? I would check the air filter. Also when it is running bad will it rev up at all?

 

[cpf240]

In line with the fuel filter thoughts, there could also be crud in the tank clogging the filter sock on the fuel pickup.

 

[corelokt]

I did change the filter and had the tank off and cleaned when I bought it. Makes sense though. I wonder why it would "rattle" at first though, and not upon restart?

 

[Jeepsinker]

Could be oil flow issues

 

[combatmech]

I'm with Triple C.... fuel delivery. When you changed the filter and tank, did you bleed the system as per the TM?

 

[corelokt]

I'm going to put a new style fuel filter and electric pump out of a 90's 6.2l truck, see how that works.
As an aside, the truck is leaking or burning oil, so it has been low, likely that is lot of it. Found black oil in the snow under the passenger tail pipe upon start up, other side was clean.