2004 Yukon P0307 "cylinder 7 misfire detected" fuel problems

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#1
Hello, Having issues with my '04 Yukon, 5.3 liter V8 VIN T (not flex fuel). Got P0307 back in March. It ended up being the fuel injector. I figured it went bad, so I repaced it. All was good. Then a couple weeks ago MIL came back on. I thought another injector went bad. Well, it was the same cylinder. So I replaced the injector again, but now I realized something else was going on. I inspected the 2 spare injectors I now have and found them to be contaminated with what looks like rust. Now I figure I would change out the fuel filter and then found there is no external fuel filter on this truck. Weird! There is a page in my GM service manual for replacing the filter, but it is not where it says it is. Apparently, the only fuel filter is in the sending unit assembly inside the tank. How unfortunate. Anyway, sorry to babble on. The bottom line is I seem to have rusty gas and no filter to clean it. I'm sure it's only a matter of time before that injector (or others) fouls again.

I did manage to hunt down two TSB's that relate to the problems I'm having. They are TSB 3055 (NHTSA #10009666) having to do with cylinder 7 misfire and TSB 3280 (NHTSA# 10013502) - rust found in injector screen inlet filter. It would be interesting to know what GM does to address this problem.

Could I install a fuel filter? Or will that cause problems? Also, the injectors I have just need cleaning, I think. Any tips on cleaning at home. It costs over half the price of the injector to send them out.

I thank you for taking the time to read this and appreciate any advise or information you may on this issue. Oh, and thanks for this quick response in helping me activate my account. Regards.
 

jasonn20

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I do not believe this has a metal gas tank they changed to plastic in mid 90's.

Some light carbon build up on the injector is normal and I has seen light brown coloration on the tip which is normal.

Not sure about your TSB as I am not able to find them as being creditable.
 
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#3
GM's fix is to run GM fuel injector cleaner through the injectors using their method. And then advise the customer to use high detergent Or TOP TIER gas as they call it. They also advise to add GM injector cleaner to every fill up which I think is overkill but that what they recommend. They know they is a problem maybe they will spend the extra 2 bucks and put a filter back in the fuel system. HTH Greasemonkey :)
 

Starbird

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#4
Look in the frame rail under the drivers door. That is where the fuel filter is. Pain in the butt to change because they used a common compression nut style connection on one end, and an internal spring clip on the other that requires a special tool. The tool generally doesn't work, so you end up going upstream to disconnect and remove both the filter and tubing, and working on it on a bench. Don't even try to release the internal spring clip with a screwdriver. It won't work, and screws up the spring clip.
 

EricC

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#5
#PIP3280D: Fuel Injector Replacement Information - Inspect Fuel Injector Inlet Filter Screen For Rust - keywords P0171 P0174 P0300 P0301 P0302 P0304 P0305 P0306 P0307 P0308 - (Sep 17, 2008)


Subject: Fuel Injector Replacement Information - Inspect Fuel Injector Inlet Filter Screen for Rust


Models: 2005-2007 Buick Rainier

2004-2007 Cadillac Escalade, Escalade ESV, Escalade EXT

2004-2007 Chevrolet Express, Silverado, Suburban, Tahoe

2004-2007 Chevrolet Trailblazer

2004-2007 GMC Envoy, Envoy XUV

2004-2007 GMC Savana, Sierra, Sierra Denali

2004-2007 GMC Yukon, Yukon XL and Yukon Denali XL

2004-2007 HUMMER H2

2005-2007 Saab 97x

with a V8 Engine

(RPOs L33, LH6, L59, LM7, LQ4, LQ9, or LR4)




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This PI was superseded to update models and condense the recommendations. Please discard PIP3280C.


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The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Condition/Concern:
Some customers may complaint of a SES light, engine misfire, or other engine performance concerns. In some instances, their concern may be the result of a plugged fuel injector inlet filter screen, which may not be repaired by cleaning the fuel injectors as outlined in 03-06-04-030.

In a returnless fuel system, all fuel leaving the tank flows through the fuel injectors because there is not a return line for fuel to return to the fuel tank from the engine. As a result, any contamination (including rust) that forms in the fuel line will find its way to the fuel injectors. The fuel injector inlet has a filter screen to filter out small contaminants, such as rust. If enough debris accumulates on the fuel injector inlet filter screen, it will start to restrict fuel flow.

Recommendation/Instructions:
If the latest version of 03-06-04-030 leads to fuel injector replacement, inspect the fuel injector inlet filter screen for rust contamination. If rust contamination is present, replace the affected fuel injector. Replacement of all steel fuel lines is also recommended whenever rust is observed in an injector because there is a chance that rust remains in the steel fuel lines.

Also inspect for rust in the fuel tank, which indicates that water may be present. If present, it could affect uncoated portions of the fuel pump and filter assembly and the fuel lines, and could lead to a re-occurrence. If rust is observed in the fuel tank, follow the Fuel System Cleaning Procedure in SI to clean the inside of the fuel tank and refill with clean fuel. Also inspect the in-tank fuel pump module and filter assembly, and replace as necessary.

Using GM Fuel System Treatment PLUS (at oil change intervals) can protect against the affects of water and certain contaminants that may be present in some poor quality fuels.

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.

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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