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Good afternoon all and thanks for accepting me..hate to have my first post as a question but here it goes, I have a 1985 corvette stock which I have had for many years, recently all of a sudden it started running rough, starts fine idle seams fine but when i take it out its rough, I did a tune up, plugs, wires, cap and still the same, I did replace the fuel pump a year ago..I put a fuel pressure gauge on the fuel rail and it reads 21psi both starting and running, i then disconnected the connection at the rear pickup at the pump and put the gauge there, still the same 21psi. from what I'm reading I should have 40+psi, would the difference be enough to have the car run rough?
Thanks in advance all
Gordon in the Keys
Last edited by Gordinthe Keys; Jan 25, 2022 at 03:09 PM.
Reason: editing title
Most likely the fuel pressure regulator. Do you have fuel in your oil? That is the common symptom of the FPR going bad as the diaphragm leaks and gas gets sucked into the vacuum line into the oil.
Most likely the fuel pressure regulator. Do you have fuel in your oil? That is the common symptom of the FPR going bad as the diaphragm leaks and gas gets sucked into the vacuum line into the oil.
I do not smell fuel in my oil and I removed the vacuum line going to my FPR and I do not smell fuel in it either
I would be looking at the fuel pressure regulator. 1/2 the pressure will absolutely cause it to run rough
I had a bad Gauge..borrowed one from a friend and i have 40psi..when bleeding the gas from the gauge the gas was cloudy...did that a few times and I have bad gas, going to pull the pump out now and drain and clean tank, blow out lines and change filter...hopefully my injectors are fine...gas on the left is from the vette, gas on the right is from my ford... will post later today
Yep it was the gas...must of got bad gas last time i filled up...not taking any chances got to dispose of 15 gal of gas, now on to the next issue. Battery is discharging over night, new battery and there is a spark when connecting the battery
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