Can people please stop hijacking threads? Then we can just focus on one person's issues at a time! As for running higher octane fuel. It should help with mpg and it should help your truck run better. These are some of the reasons it costs more. At your next fill up put in higher octane, see if you like the results! It wont hurt.

 

It's possible. Simple to test though. Any exhaust shop should be able to do it up for ya.

 

ya I am filling up with premium today still not sure about the cat I removed the throttle body today the iac was completely covered in carbon I am cleaning that today to. also removed a spark plug looked like it was running a little lean? any relation to the iac?

 

Have you tried pulling the o2 sensor before the cat and see how its running?

 

I pulled it and looked at it I replaced it last summer it looks fine

 

Have you tried running the truck with the sensor still out?

 

no I have not what will that do?

 

If the cat is clogged, removing the front O2 sensor will relieve some of the exhaust back pressure that builds up....if you remove the front o2 and the truck doesn't run any better or worse, then you can likely eliminate the cat as the problem

 

It will take more than one tank of premium gas before you start to notice a difference. It will take at least three tanks of premium before you start to see a difference. All of the lower grade gas has to be used up, then the computer needs time to adjust to the higher octane gas.

 

Could you not run it almost completely dry(eliminating most of the old gas) then reset the pcm? Would be closer to premium in a faster time.