Need help reading these numbers / rough idle

[Bigred81]

1999 CK1500 suburban 5.7 liter 4X4 with 245,000 miles.
First thing. I’m almost at rock bottom in life. So much going on. I could really use some help figuring this out.

3 months ago I wanted to fix exhaust leak, oil leaks. I replaced Oil cooler lines, Oil Pan Gasket, Oil Pump, Timing Cover. I never touched anything mechanical other than oil pump. Got done and NO SPARK!! I replaced Distributor Cap, Ignition Control Module, Coil, Lead Wire, Knock Sensor, Crank Shaft Positioning Sensor, fuel filter and fuel PSI was at 63 or 64 PSI. No spark. Towed to shop with flawless reviews. Took them 11 days to get to it and two days to fix. They adjusted timing and replaced wire harness for Ignition Control Module and new battery. Burb ran great and started in under 1 RPM. 1 week later a little rough running but whatever. I have no money and wife and kids aren’t well.
Today I’m driving along and all of a sudden it’s barely running. Coast down a hill and put in code scanner. Went and got a new O2 sensor for upstream passenger and MAF. It barely starts and won’t idle. Replacing those did nothing. I know I should take it back to shop that fixed it but I can’t afford to not have a vehicle to drive to work or I’ll lose everything.
im getting code P0174. I took pics of the read outs. I replaced the injectors with AC Delhi MPFI and fel pro gaskets for intake gasket. I sprayed starting fluid to try to find vacuum leak. No change
what’s next?
while writing this I’ve been researching. I did have a random misfire code as well. Apparently when people replace there entire distributor it’s been known to fix it. I hate the shot gun blas method of fixing. Hopefully someone can help.

 

[Schurkey]

1999 K1500 suburban 5.7 liter 4X4 with 245,000 miles.

OK.

I’m driving along and all of a sudden it’s barely running.

What is the fuel pressure?

im getting code P0174. I took pics of the read outs.

P0174 is a lean code. Your fuel trims are trying to make the engine run even more lean. Doesn't make sense to me.

Misfire causes FALSE lean reports from an O2 sensor. Fix the misfire, the lean O2 sensor fixes itself.

TPS reading of 0.0 seems suspicious.

 

[honkon]

No codes beside P0174? Your total fuel trim at idle is nearly -30%. The computer is doing the most it can to correct for a perceived rich condition.
See what the fuel trim is under load while driving, also observe upstream (S1) readout at WOT. Should be nearly pegged at .9-1v.
I see B1 upstream o2 reading .070v at idle. Does it stay constant or does it switch between 1 and 0 volts?

 

[Bigred81]

OK.

What is the fuel pressure?


P0174 is a lean code. Your fuel trims are trying to make the engine run even more lean. Doesn't make sense to me.

Misfire causes FALSE lean reports from an O2 sensor. Fix the misfire, the lean O2 sensor fixes itself.

TPS reading of 0.0 seems suspicious.

pressure?

Not sure about current fuel pressure. Was at 63 psi two months ago and I replaced fuel filter for fun.
yes P0174 is only code.
Okay will do. New distributor assembly came in today along with new ac delco plugs and wire and BOSCH O2 sensor. Gotta get it at top dead center then pulling old dizzy and putting new one in. Passenger side plugs looked pretty hammered, and two of them had a decent amount of fuel on them. Wished there was a manual on this exact engine with what readouts should be with trouble shooting each problem.
Would a wet spark plug indicate more along the lines of ignition issue? Over a fuel issue.

 

[Bigred81]

No codes beside P0174? Your total fuel trim at idle is nearly -30%. The computer is doing the most it can to correct for a perceived rich condition.
See what the fuel trim is under load while driving, also observe upstream (S1) readout at WOT. Should be nearly pegged at .9-1v.
I see B1 upstream o2 reading .070v at idle. Does it stay constant or does it switch between 1 and 0 volts?

Yes that’s the only code. Okay will do. New distributor assembly came in today along with new ac delco plugs and wire and BOSCH O2 sensor. Gotta get it at top dead center then pulling old dizzy and putting new one in. Passenger side plugs looked pretty hammered, and two of them had a decent amount of fuel on them. Wished there was a manual on this exact engine with what readouts should be with trouble shooting each problem.
I will check O2 readouts. As for wide open throttle? I don’t know if it will even run good enough to get there. I will check tomorrow after I get it put back together.

 

[Bigred81]

Yes that’s the only code. Okay will do. New distributor assembly came in today along with new ac delco plugs and wire and BOSCH O2 sensor. Gotta get it at top dead center then pulling old dizzy and putting new one in. Passenger side plugs looked pretty hammered, and two of them had a decent amount of fuel on them. Wished there was a manual on this exact engine with what readouts should be with trouble shooting each problem.
I will check O2 readouts. As for wide open throttle? I don’t know if it will even run good enough to get there. I will check tomorrow after I get it put back together.

And thank you for your help and time.

 

[Bigred81]

Yes that’s the only code. Okay will do. New distributor assembly came in today along with new ac delco plugs and wire and BOSCH O2 sensor. Gotta get it at top dead center then pulling old dizzy and putting new one in. Passenger side plugs looked pretty hammered, and two of them had a decent amount of fuel on them. Wished there was a manual on this exact engine with what readouts should be with trouble shooting each problem.
I will check O2 readouts. As for wide open throttle? I don’t know if it will even run good enough to get there. I will check tomorrow after I get it put back together.

Thank you for trying to help. I appreciate it greatly.

 

[Bigred81]

I replaced plugs, wires and distributor. It runs better than it did. I know I’ve gotta take it in to get the timing done now. I’ve got more codes now which is expected since timing needs to be done. There is one I’m worried about though.
It’s P1351
1. IC circuit high voltage
2. IC circuits 1&4 malfunction.
once again all ignition components are new but this is a voltage thing. Hopefully timing fixes it.

 

[Schurkey]

"Timing" isn't going to fix anything. Your ignition timing is not adjustable. The computer pulls base timing off of the crank sensor, and everything is electronic from there.

Best you can do is use a scan tool and twist the distributor to get the crank sensor and cam sensor in synch.

Clear the codes, see what comes back.

 

[Bigred81]

"Timing" isn't going to fix anything. Your ignition timing is not adjustable. The computer pulls base timing off of the crank sensor, and everything is electronic from there.

Best you can do is use a scan tool and twist the distributor to get the crank sensor and cam sensor in synch.

Clear the codes, see what comes back.

I tried that and it says the same. Wondering if I missed a tooth when installing distributor? I had it at TDC on compression stroke and I thought 100% that I had it lined up right. Thought about doing the trick of drilling a hole by one of the contacts in the distributor cap so I can see if the spark isn’t sparking straight up and down. On the old cap of course.