Honestly, there is nothing anyone on this forum can do to help you. At 589 HP your LT1 is far from stock. I can't imagine using it as a daily driver. I assume the engine is normally apsirated or were those numbers hit with a supercharger? if N/A, how does the thing even idle at a stop light??? You need to head to a dyno tune shop that does LT1's and prepare to spend some cash.

 

lol only 7-8 miles a gallon with a 10 gallon fuel cell on it...... it idles perfectly untill the check engine comes on then it trys to shut off...had it scanned again but still no codes so i made the dam SES light come on just to see if the computer was reading it and it was cause i unpluged a O2 sensor and the MAF and the computer scanner found both then i hooked them back up and nothing lol and no supercharger or turbo dam no room hahahah..already had it dyno tested before it messed up but now i might hit 372 lol when the rpms drop...i mean i dont drive it hard at all maybe once in a while ill open her up to keep things going i guess lol

 

589HP and it idles perfectly?????? I guess what I would describe as perfect idle for a daily driver vs what you do may be different. I don't consider idling at 1300-1500 rpm and still loping to be perfect idle. But, i get ahead of myself. Please feel free to list what was done to get to 589 HP including the fuel system, heads, lower end, ignition etc.

I also assume that it is no longer 350 CID. You really need to go to a specialty shop and my curiosity is also piqued as to what was done to hit 589HP on a normally apsirated LT1 without spraying it.