58 Corvette with 1987 L98 engine, stock ECM, external Walbro fuel pump: Running great for months, then died one time 5 miles from home a while back, and immediately restarted - drove home with no problem. Then later, about 5 miles from home started coughing through the intake and sputtering (just like earlier) - eventually died after turning around to head back home. Waited 40 minutes restarted but hardly ran - called tow truck - embarrassing. Once home the car restarted - barely running but noted small amount of white smoke from left exhaust. Never any codes were thrown. Reset lifters from one turn past zero to 3/4 turn. Vacuum is good at 15 - 17". Checked compression and it was all around 120-130 PSI. #5 & 7 spark plugs are just a bit darker than all the others. Did coolant pressure check and it was good. Started and it was smooth and solid - went for test ride and performed well. Stopped at a neighbors about 300 yards from home - spent maybe 3 hours - went to drive back home and barely made it back. Engine would either run good for a short while or start sputtering and backfiring. Thankfully it ran strong for a few seconds to get me up my driveway and into the garage. Recently replaced everything in the distributor – no change. Runs terrible with the TPS connected or disconnected. I believe my grounds are good but I could be missing something there. Fuel pressure comes up to 45 PSI but will bleed down to 5 PSI within a few minutes. I then had someone turn on ignition in order to bring pressure up and I immediately shut the valve between the fuel tank and the pump. Same thing – pressure bled off in about 3 minutes to about 5 PSI then it takes a long time to go to zero. Any suggestions?