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I was afraid of that. But the larger context is that the engine is misfiring (See https://www.gmt400.com/threads/misfires-return.62862/) and fuel pressure is an issue I can't seem to resolve.
From the service manual:
When it is idling I drop from 51-52 to 49-50psi - I assume that is due to intake vacuum/regulation. I have done a lot to diagnose the misfires and the fuel pressure seems to be the last thing. Here is the reader digest version. Replaced plugs, coil and wires. I did compression and leak down tests (all looks good). I had a bad disty (worn down cam gear), replaced and cam retard adjusted. Had high fuel trims caused by lazy O2 sensors and intake leaks, both fixed and FT are significantly lower. Fuel pressure is the last thing on my list. At a loss.
How do you do that?My engine ran lean until I swapped the correct injector data into the tune.
Tuning the PCM. I stole the injector data out of a 2010 or so 4.3L that uses the upgraded spider as OEM. On 10% ethanol with the wrong injector data my 97 was lean with long term fuel trims approaching +20%.How do you do that?