JrRifleCoach

The fuel pressure must increase to RPM/vacuum demands. When the throttle is blipped pressure should increase +10 PSI (approx). The O2 sensor does not play a part in this event. It will compensate during other steps but the first step is all vacuum to kickup FP. FP fluctuations can be fuel dilevery. Pump, fuel filter, FPR are the basic components to check first. A quick check is to place a vacuum guage on the vac line to the FPR. Make sure there is good vacuum and that this value changes when the throttle is blipped. Check the FP for changes during this test. IF the FP stays constant, then you can chase the vacuum line for cracks or disconnects.

I used rubber vacuum hose to replace damaged plastic lines. Just cut out the section and splice in some rubber hose.
























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Hookdbyvettes

Sorry to the fellows who were nice enough to take interest in my problem, not writing back sooner. My vet found cancer in my dog, tomorrow she operates on him. It's possible, but doubtful she'll be able to get it all. Any-hoo...... I took the vette to a local mechanic I think I'll be calling my mechanic. We spent hours allowing it to cool off, then he hooked up a machine that monitored many of the specs of the engine. While I haven't checked the simple things you guys instructed, he (my mechanic) told me after the engine had run for 4 minutes it appears the loop closed which would indicate the O2 sensor is working, though since I've purchased a new one, he figured I should go ahead and install it since we had no way of knowing how old the one that is already there (after fixing my current issue). It's also running lean. I have failed to tell you guys that I have paid enough attention to see a cloud of blue smoke when starting after sitting over night. The injectors were supposed to have been replaced six months before it went on sale, with stock models picked up at the local parts store (according to the seller). They are shiny and appear clean, but if I must replace them, I'd like to replace then with the newer models that I've seen many on the site suggest for those having to replace a full set of injectors (and the 9th one). It would take a few searches, but they are supposed to be much better that what the '86 stock vette ran. Hopefully I'll have the time to test the vacuum, regulator and go buy a new filter, which appears to have been replaced when the injectors were, it looks very fresh, though no reason leaving anything to chance. I'm guessing a bad fuel pump is a real possibility with 30psi at idle and the pressure dropping to 28-26psi when stepping on the gas under load. I attached the fuel pressure gauge & had both windshield wipers holding it in place while I drove. Both engine and pump were hot from being driven on the highway for a 20 min drive before the test. I read the pressure should be almost double what I have under load and 15psi more at idle. I guess my worst worry is removing the plenum, which I've never done. I suppose that's why I'm worried. Thanks to you guys who have been helping me, H.