Hello everyone
new to this forum, hoping somebody can help. here goes.

I have a 98 chevy 2500 pu. w/ about 150,000 miles on a 5.7vortek.
started feelin a miss bout a week ago. changed plugs & wires. no help. A friend has a snap on diagnostic unit. showed misses on cyl. 4 & 8. but no other problems except some o2sensor activity. low activity i think it was, also the check engine lite is NOT on.
when im stopped at a light, it feels like it wants to surge forward. in neutral u can really feel the misses bad. when im driving i also feel it surging, or cutting out, and it has no get up and go.
my question i guess is, what else can make it miss like this. thinkin fuel injectors.but the snap on unit said they were ok. please help.
thanx, Bob

I'm not sure about your particular engine, but does it have a distributor? If so, did you replace the cap and rotor when you changed the plugs and wires?

you can inspect the rotor and cap but its likely the pos spider injector. what are your ltft'* and stft'*? whats your fuel pressure koeo and started at idle reved?

As jwfirebird said, my 2cents is on the efi spider, more particularly the "poppets" in the ports.

The actual injectors are centrally located below the upper intake manifold - They "fire" (snap-on thinks it'* all good) and the pressure pushes the proper spring-loaded poppet open for that cyl. (go figure)

I recently replaced the whole mess with the Delphi (OEM) upgrade $180ish amazon
It moves the injector out to the port - bolt on & runs great

Oh, the $180ish was for my '98 sonoma 4.3V6 - yours is similiar.

And ditto on the "good" cap & rotor

luck,greg

I'm leaning towards fuel since you said "o2 low activity & surge" in your description.

luck,greg

I have a 98 same as yours i just up graded the spider assembly. It cost me 299 at Autozone.

amazon has the v8 one for 250ish

thanx everyone for your input. I didnt change the cap & rotor.but i inspected them.they seemed ok. so fuel. see i was hopin to not spend money on things that aint the problem, like i usually end up doin. let me check out the fuel sys. ill let u know
thanx again Bob.