gerkendave

For a long time I had a system flow during non purge code on my 2000 Chevy 1500 with the 5.3 so I replaced the purge solenoid on the intake and cleared the code. The light went away for almost a week and then it returned now with a bank 1 too lean, bank 2 too lean, random misfire, and catalyst below threshold. After some research I had decided to clean the MAF, clean the throttle body, change the fuel filter and also check the fuel pressure regulator. After all of this I cleared the codes and they returned within two days. My question is could I have torn an o-ring on the purge solenoid causing it to draw air or what should I check next.

EinST

Not to question your understanding and interpretation but could you post the actual codes (and freeze frame data if available)?

gerkendave

PO171, PO174, PO420 and I forgot to right down the random misfire code just remember that it showed up.

EinST

So, is this the same vehicle as in your other thread https://chevroletforum.com/forum/sil...lverado-41568/? How does it drive in general and specifically how does it idle? I'm wondering if the purge pipe didn't come off the purge solenoid. If that's the case, it'll go lean both banks as soon as the PCM performs the EVAP purge valve leak test which wouldn't really affect drivability.

gerkendave

Yes its the same pickup. I just pulled the valve off the intake and everything there looks good. Also I used carb cleaner and shot around my intake looking for an intake leak with no prevail. While driving down the highway at 55-60 the truck has a slight but annoying fluctuation in the rpm. Also at times the idle while in park is slightly up and down as well but not much

gerkendave

OK went back and re read the codes, this time I only have one and it is the PO420, Catalyst System Efficiency below threshold bank 1. the freeze frame data was as follows
Fuel System 1......CL
Fuel System 2......CL
Calc Load ...........1.9%
ECT....................197*
STFT B1.............-2.3%
LTFT B1.............12.5%
STFT B2..............-1.5%
LTFT B2..............10.1%
MAP...................11.8 inHg
Eng. RPM.............526
MAF................. .671 lb/min
tps.................. .3%

Is it my O2 sensor on bank 1?

EinST

It looks like you have multiple problems. The long term fuel trim values say you're running lean. Since both banks are affected, you probably have an air leak or low fuel pressure. Maybe it wasn't apparent before when you were leaking fuel vapors into the intake through the leaky purge valve.

The MAP sensor is reporting too high air pressure (too low intake vacuum, the same thing) for the engine at idle. Combined with P0420, you probably have a clogged catalytic converter. Get the exhaust back pressure tested both pre-catalyst and post-catalyst.

gerkendave

Just an update on whats going on I've flip flopped the two rear o2 sensors did an intake cleaning with seafoam and also a fuel system cleaning with seafoam and replaced my k&n intake with the stock one cleared the codes and for the past three days the light has stayed off.