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The truck is a 1998 Chevy K1500 with a new short block 5.7, 8 k on the engine, 128 k on the clock. Transmission rebuilt just over 1000 miles ago and woks flawlessly.
The issue does not exist in open loop only in closed loop. All sensors, distributor, cap, wires, plugs, Egr, o2 sensors, coil, are new.
The truck runs fine with no misses except at highway speed say 65 or 70 until you slightly reduce throttle pressure ever so slightly. For example: I’m cruising on a level road and approaching a small grade I slightly accelerate to maintain my speed and once I clear the very small grade and reduce accelerator pressure I get a big miss as if no spark for just a micro second. It’s as if I just shut the key off and back on just as quickly as I could. Any passengers can also feel it. It happens very quickly, it’s all cylinders and it only at throttle reduction. I have no problem in acceleration, no misses and runs smoothly. I do not have the problem in open loop and I only have an OBD2 reader, no scanner. No codes
Any thoughts would be great. I’m in Yuma AZ but having difficulty locating a legitimate mechanic who won’t just throw parts at it. Been there more times than I care to admit.
