I scanned my car today, and took first up to 4k, no knock retard, took second up and felt the car stumble a little and it took out like 8-9degrees of timing. I have the LT4 k/m, a brand new k/s, and a pcmforless tune.

My fuel presure gauge is messed up so I havent had a chance to check the presure, but does anyone see how fuel delevery could cause this condition?

BTW- I replaced my bad o2 sensor (my o2 readings look fine now), and nothing that I could see on the datalog followed the stumble. So thats what leads me to think that it could be fuel related.

Anyone had fuel delvery probs after car has been sitting for a few months, the car isnt hard to start (unless its been sitting for a few days, then it takes a while).

Thanks,
James

 

ttt

 

YES it can cause knock with a worn pump or low pressure but most of the time the car just lays down.
Do a board search and get the number of the resistor to put inline with the KR if you think you have false knock from rockers or headers.

 

most definately!baaaaaad things happen when you lean out!