The engine is misfiring I changed spark plugs

I have 2000 silverado 4.3 that has been acting up. It idles fine and always starts right up but when ur accelerating right before it shifts around 3500 to 4000 rpms it misses. Some times it just shudders and chugs sometimes it just falls completly on its tail and loses all power and will either go on die or it will catch back up and take off sometimes it will backfire. Once it has started messing up alot it will do it if ur just cruising or coasting but alot worse when ur accelerating at higher rpms. Its like it just loses fire I have checked fuel preasure, tps, changed plugs and plug wires, dis cap and checked resistance of the coil. Nothing helped. It seems to only do it when its warmed up and is worse when it is hot outside like 100 deg. Thanks

Only light it gives is random misfire and p1351 and the tack just falls.

The truck listed above is 1500 with a 5.3L engine. I have a random misfire and I can't find the problem.

My 99 silverado 2500 6.0 is having misfire issues. It has misfires in every cylinder. Some rarely misfire and some misfire a lot. I've changed plugs wires and 3 coil packs on the worst cylinders. Checked fuel pressure and flow. Could it be the ecu? Or maybe valve springs or lifters?

A new fuel pump fixed it for me, thanks for the guides.

Truck was missing so I replaced the plugs and wires and still missing, only when I give it gas though. Is it gas or the ignition coil?

I've changed fuel filter, plugs, wires, rotor, distributor cap, ignition module and it still isn't fixed what else is it

Just the p0300 code compression was about 120

Bad coil was it thanks, runs great again.

Truck listed above is a k1500 5.7 TBI. Engine missing pretty bad hot or cold in park and drive. Has new TPS, MAP, EGR, IAC, temperature sensor, plugs, wires, and distributor. A/C is unhooked.

5.7L (350CI) Throttle Body Injected automatic with 126,000 miles. A while back I had bad misfiring (sputter, missing, and stumble) while accelerating and in the last gear under greater load i.E. Going up a hill (truck would shake and stumble) but not much while idling (slightly if at all) Replaced plugs (two plugs and ash deposits and one plug had oil on it) and fuel filter (filter poured out brown gasoline) and it ran like a champ for about a week.

Started doing the same thing again and also missing more at idle. Replaced wires, distributor cap, and rotor button. Wires had arcing spots, distributor cap was corroded and worn, rotor button was rusted onto the distributor and had lots of black deposits, the circular metal plate where the cap screws down on was solid green with corrosion, removed as much as possible but unable to remove it all. Solved the problem and ran wonderfully for a couple weeks to a month.

Now it is miss firing again while idle (worse than before) and while accelerating and cruising in last gear under load i.E. Going up a hill EXACTLY as before. Hoping it's not a warped or burned valve, especially since it ran like a champ for a while after every repair.

(As a side note, kind of unrelated, after the wires and distributor cap and rotor button, I had the intake manifold gasket replaced for leaking, valve cover gaskets replaced for good measure, and driver side exhaust manifold replaced because of a crack, done by a shop. The mis firing started a week or two after these repairs)

No black or blue smoke.

Stumped, any help would be greatly appreciated, Thanks in advance!

P.S. After replacing wires, the plastic clips unavoidably broke, some of the wires are touching metal brackets connected to the block, and I caught a couple wires touching the block, so I tied them back out of the way with zip ties. Should I wrap them in plastic electrical lume where ever they contact the metal brackets to prevent arcing?