Before I post just want to say thanks in advance. This happens no matter if cars hot or cold, and at different times. Sometimes I have a power loss, and when i do, i have a slight miss and have popping out the exhaust but not a full backfire. The idle is different, still smooth but not quite as smooth as it gets sometimes. This seams to happen randomly. Open or closed loop doesn't matter. No cats and have long tubes. I did a data master log and seams like its lean all the time. Have a new Delco fpr on it and I know I need a new pump cause fp drops to zero very quickly.

 

I suggest you monitor your fuel pressure at the fuel rail to see if you're consistently have proper fuel pressure. Have you scanned it for codes?

 

No codes. And i was borrowing a pressure gauge. All we did was test at idle and after i shut it off, it drops to zero in just 30 seconds after shutoff. Im ordering a racetronix pump today and swapping and see if anything changes. I know your supposed to check it under load but at idle its 38 and rev it goes to 43 or so.