I have an '89 Iroc L98. It has 60k miles on it. I went to check the fuel pressure and primed the rails by turning the key on and off with the fuel pressure guage connected. It initially read 46psi but after about a minute it dropped 2psi and 5 minutes it read 40psi. It will probably be at zero in about 20minutes. I have checked the AFPR and it has no leaks, no leaks on new fuel guage eighter. I have heard that the TPI fuel rails should hold pressure for like 10hours. What could be wrong?
Thanks!!

 

That isn't entirely uncommon.
If you have no external leaks, then it is bleading of through a/some leaky injector/s or back through the fuel pump. If it doesn't black smoke out of the exhaust when you fire it up after it has been setting a while (bleeding pressure) then it is likely leaking back through the pump. Not a big deal unless it gets excessive.

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Tracy /AKA IROCKZ4me
'86 IROC-Z Camaro
"Cogito ergo zoom"

• 355 cid
• AFR heads
• Arizona Speed & Marine hydraulic roller cam w/ AFR hydra-rev kit
• modified SLP runners
• TRW forged pistons/ceramic coated
• fully balanced
• Edelbrock headers/ceramic coated
• SLP cat-back
• Paxton supercharger
• Nitrous Express nitrous oxide

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