P0300, p0155, p0165

[mjdemaris]

Ok, here's a puzzle.
The problem began as a random engine misfire, gradually getting worse over a couple weeks.
I let it sit for a bit, no time or place out of rain to work on it...
Started back up and ran fine for about 3 miles, then running rough again. So, I went down to Oreillys, had the code read and then I:
1. replaced fuel filter
2. checked fuel pressure
3. replaced plugs and wires
4. cleaned the MAF
5. cleaned the points and rotor - they were not that bad...
Started it up and still runs rough. Pulled the codes again, and read some live data. Now, I have a stored code: P0300, same as before, and three pending codes: P0155, P0161, and P0300.
So, I checked three out of four O2 sensors, and they appear to be good, meaning the heater circuit showed about 4.5 ohms.
I have NOT checked the voltage coming to the sensors yet, was going to do that today but the weather turned sour.
The big question on my mind is what would cause the 0155 and 0161 codes to be pending? And, second big question, what do I check next? (besides the voltage to the O2 sensor.)

I also have some live data:
RPM: 683
Fuel system 1: CL_fault
Fuel system 2: CL_fault
output voltage: B1S1: .070
B1S2: .825
B2S1: .315
B2S2: .425

ECT: 140
STFT: -4.7, 23.4
LONGFT: 0.0, 0.0
MAP: 10.0
IAT: 54F
Load_PCT: 3.5

I don't know if any of this helps or what it tells you, but there it is.

[j cAT]

fuel pressures key on engine off ? pressure engine on ?

[777stickman]

We need to know what year and engine??

[mjdemaris]

Key on, engine on, running.

1999 k1500, 5.7L
4wd

[mjdemaris]

Ok, this is weird. The Chiltons manual says that all V8s, from 99 to 06, have coil packs, one for each cylinder. Looking at the engine, I definitely see a distributor. As mentioned in a separate thread, I removed the cap and checked the points and rotor.

I am looking up the information to bench test the coil in the book.

So, it appears that the coil resistance figures in the V6 section may apply to my V8. Stating that the primary resistance is about 0.1 ohms and the secondary from 5k to 20k ohms.

If you all have additional advice, I'm listening.

[j cAT]

Originally Posted by mjdemaris

Ok, this is weird. The Chiltons manual says that all V8s, from 99 to 06, have coil packs, one for each cylinder. Looking at the engine, I definitely see a distributor. As mentioned in a separate thread, I removed the cap and checked the points and rotor.

I am looking up the information to bench test the coil in the book.

So, it appears that the coil resistance figures in the V6 section may apply to my V8. Stating that the primary resistance is about 0.1 ohms and the secondary from 5k to 20k ohms.

If you all have additional advice, I'm listening.

what is the fuel pressure ..in PSI ? engine on ? engine OFF ? key on .

[mjdemaris]

Last I checked, after replacing filter, was around 55psi.

[j cAT]

Originally Posted by mjdemaris

Last I checked, after replacing filter, was around 55psi.

what is the fuel pressure ..in PSI ?


engine ON ?

engine OFF ? key ON

[mjdemaris]

Finally found the cause! replaced the cap and rotor and she's running like a champ. about 17 mpg now.