Engine problems, need advice

Hey guys,

new to the forum and I need some help. My truck is having problems and I can’t pin it down. It’s a 97 z71 with a vortec 350. The truck had almost 300000 miles but the engine has about 100000. Good cylinder pressure and not smoke or rattles with 25-30lbs of oil pressure at hot idle. My problem is the truck will randomly have what I first suspected was fuel problems.
Driving down the road at normal speed (45-60) it will suddenly start to lose power and buck and jump like it’s losing fuel pressure. Sometimes several times, sometimes only once or twice. I changed the fuel pump and filter as I had both brand new from another project. That didn’t help but pressure is around 58-60lbs at idle. I also changed the distributor cap and rotor and tested the plug wires resistance and checked the plugs. All seemed fine and show a nice even light brown color. The only other issue I’ve noticed is that every once in a while, the idle will be high, around 1200 for 2-3 minutes. The only code in the computer is an o2 sensor heater. Any suggestions on where to start? I did a search but didn’t find anything like this issue and I’d really appreciate any help.

WHICH O2 sensor is throwing the code?

How old are the rest of them? When my truck was throwing O2 heater codes, I scrapped all four of them. Problem solved.

If fuel pressure is good, and the cranking compression is good, the answer is in the data stream. Connect a scan tool, look for anomalies.

I'd also check Vacum lines. Something as simple as this has caused me issues in the past, but mine was at take off underload. Check the pcv valve and hose if it has one ( im not sure if the vortecs do or not).

Could it be egr?

Schurkey, The only scan tool I have is a code reader unfortunately. I’ll see if I can find someone local through that might let me borrow one. It’s the passenger side rear sensor giving me the code I have. I tried changing it but it’s a real pain in the location it’s in.
Mike, I didn’t see any obvious vacuum line or wiring issues (nothing broken or missing) but I’ll get a better look today. I could have overlooked something. I thought about the EGR but it’s not stalling out exactly. It just acts like it’s not getting the correct amount of fuel for a few seconds.
While I did the cap and rotor, I also took a good look at the distributor. It doesn’t seem to have any issues, damage or play in it.

I appreciate the help and ideas guys.

Did this ever get fixed? Have the same problem on my 98, any help would be greatly appreciated