Problem: about 3 weeks ago, PO332 came up on the SES reader (snap on), it said my Knock Sensors went bad, so I tore my intake apart 2 weekends ago, then replaced my knock sensors and put everything back together. once i was finished, i restarted my truck and it began to "buckle" on me really bad. I went over every connection and everything was connected right, but still buckled. I ran the codes and up came PO300 and PO200. I checked my injectors, after unplugging numbers 1, 3, 5, & 6, it hit me something else was wrong, maybe a plug or sensor was broke. so i took of the manifold again this weekend and checked the knock sensor wiring. it turned out one of the wires wasn't plugged fully. so i did it once more, took it all off, rechecked it all, and still, buckling. the only code that came up this time was po300, random misfire.

Problem: Random Misfire.
Caused By: Reinstall of knock sensors (2 new ones)
Solution: maybe one of you guys know whats going on and can help? any ideas?

If any one can provide some assitance, I will be oh so thankful. my truck has been sitting for 3 weeks and i am going nuts with out her.
Thanks!

 

I had that problem before and it was bad fuel injectors.Tried cleaning them with the top end cleaner you can get at the dealership,but still had to replace them.I suggest flow testing them at least.

 

Sounds like the same thing that happend to me today. I tore my intake off to replace a knock sensor, put it all back together and started to miss badly. Scanned it and had an injector fault and a missfire code. Swapped wiring around on two injectors, and found one injector to be dead. Was NOT my day.

Kyle

 

Hey Buddy,
Sounds like your're having what I call a "ghost in the machine" problem. The good news is, I think I can help. If you will email me the codes and a description of the problem and what you've tried to do to correct it, then I will check out the codes at work and talk with a couple of my Techs and see what I can come up with. Are you cool with that? If so, email me at.........
josh_evanz@hotmail.com

10 years experiance w/GM Vehicles, ASE Certified Technician, ASE Certified GM Parts Technician, GM Warranty Service Advison, GM Dealer Service & Parts Manager @ Modern Sales & Service Inc. Grundy, Va.

 

It Could Be A Few Things Check With Some Water Are Brake Clearner If You Have A Intake Leak Pull Off Fuel Rail And Pull Off Inj. And Inspect Each One. The Scan Tool You Used Should Be Able To Tell You What Cyc. Is Misfireing But Watch It Could Be The Cyc. Before With The Problem.it Does Not Sound Like Any Thing Majior. Check That And Let Me Know.

 

You need to go over your work again very closely since you didn't have this problem before you started the job. Did you pinch a wire? Were you very careful that everything was out of the way when you dropped the intake back in place? It helps to label everything and tie stuff well back out of the way to avoid getting a wire shorted to ground during reassembly. The labels help to be sure everything goes back onto their proper connectors. Digital cameras are a quick and simple aid to reassembly. You can review the photos you took before the motor was pulled down to help in being sure everything goes back correctly.

 

i warranty a lot of number 8 injecters due to water intrusion from the fuel system infact there is a bullrtin on this

 

Where might I find this bulletin? https://ls1tech.com/forums/showthread.php?t=247636

 

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Tech - Engine Misfire, Water in Fuel, SES Lamp Illum., DTC P0300 Set #00-06-04-024 - (Jun 1, 2000)
Engine Misfire, Water in Fuel, Service Engine Soon Lamp Illuminates, DTC P0300 Set (Replace EVAP Canister Vent Hose Asm/Replace EVAP Canister If Necessary)
1999-2000 Chevrolet and GMC C/K Pickup Trucks (Silverado and Sierra)

Built Prior to August 31, 1999

Condition
Some drivers may comment about the Service Engine Soon lamp illuminating. The Powertrain Control Module (PCM) may have stored a Diagnostic Trouble Code (DTC) P0300, Engine Misfire Detected. The engine may be exhibiting a misfire, possibly in the #7 and #8 cylinders. This condition may also affect the six cylinder models. This condition may be more prevalent in areas with high amounts of rainfall.

Cause
Diagnosis of the fuel system may reveal the presence of water, possibly in the fuel rail near the #7 and #8 fuel injector. Water entering through the evaporative emission (EVAP) canister vent solenoid may cause this condition. Because of this, an engine misfire may develop.

Correction
A new EVAP canister vent hose assembly, P/N 15759042, that includes the valve and the solenoid has been developed to correct this condition. The new solenoid has a revised mounting bracket and a sealant has been applied to the top lid seal surface of the solenoid to address water intrusion. Use the procedure and the part numbers listed below.

If standard diagnostics do not lead to the resolution of the misfire, do the following steps:

Remove the fuel rail at the #7 and #8 fuel injector from the engine and drain the fuel into a suitable container. Inspect the drained fuel for the presence of water. Refer to the Fuel Rail Assembly Replacement procedure in the applicable Service Manual.
If the presence of water is detected in the fuel rail, remove the fuel tank and inspect the fuel for the presence of water. Refer to the Fuel Tank Replacement procedure in the applicable Service Manual.



If water is present in the fuel tank (other than from a water enriched fuel fill), replace the EVAP canister vent hose assembly. Refer to the EVAP Vent Valve Replacement procedure in the applicable Service Manual.
Disconnect the EVAP canister line connections and remove the canister. Inspect for the presence of water at the canister line connections and inside the canister. If water is present, replace the EVAP canister. Refer to the EVAP Canister Replacement procedure in the applicable Service Manual.
Flush and clean the fuel system. Refer to the Fuel System Cleaning procedure in the applicable Service Manual.
Parts Information
Part Number
Description

15759042
Hose Asm., Evap. Emis Cnstr Vent (includes solenoid w/bracket and hose)

17113596
Canister, EVAP Emis

(Long Bed)

17113539
Canister, EVAP Emis

(Short Bed)


Parts are currently available from GMSPO.

Warranty Information
For vehicles repaired under warranty, use:

Labor Operation
Description
Labor Time

J6391
Solenoid, Evaporative Emission Canister Vent Control - Replace
0.3 hr

Add
For Diagnosis Time
0.3 hr

Add
To R&R Fuel Rail
0.6 hr

Add
To R&R Fuel Tank
1.1 hrs

Add
To Replace Fuel Vapor Canister
0.2 hr




GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.
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