found this online:

Re: E85 2004 Tahoe Problems

New TSB:

Vehicle With Flexible Fuel E85 (RPO L59) Will Not Start, Loss of Power, Poor Performance and/or Fuel Gauge Reads Inaccurate/Incorrect (Replace Fuel Pump Strainers AND/OR Redesigned Fuel Level Sensor)

Models: 2002–2004 Cadillac Escalade
2002–2004 Chevrolet Suburban, Tahoe
2002–2004 GMC Yukon, Yukon XL
with 5.3L V8 MFI Engine and Flexible Fuel E85 (VIN Z — RPO L59)
__________________________________________________ __________________________
This bulletin is being revised to announce the availability of a fuel strainer kit. The release of this kit allows
the technician to replace the fuel strainers without replacing the entire fuel module. Please discard Corporate Bulletin Number 04-06-04-012B (Section 06 — Engine/Propulsion System).
__________________________________________________ _________________________

Condition
Some customers may comment that the vehicle may not start, experience lack of power and/or driveability concerns.
Some customers may comment that the vehicle appears to be out of fuel but the fuel gauge reads above empty.

Cause
There are two possible causes for this condition:
Important:
•The first possible cause is contaminates in the fuel may plug/restrict the fuel strainer on the bottom of the fuel
module.
•The second possible cause is that the vehicle is actually out of fuel but the fuel gauge reads that there is
sufficient fuel in the tank. This condition is caused by contaminates on the fuel sender card, causing inaccurate
fuel gauge readings.

Correction
DO THIS
Don't Do This
Replace the appropriate Fuel Level Sensor and/or the Fuel Strainers.
DO NOT Replace the Complete Fuel Modules P/N's
88966962
88966963

Follow the service procedure below for diagnosis and correction of these conditions.

Important: The fuel level sensor may be sending the fuel gauge false readings.

1. Confirm that there is actually fuel in the fuel tank. DO NOT use the fuel gauge to confirm fuel tank level.
•If the vehicle has fuel in the fuel tank and the vehicle is experiencing driveability concerns or a no start, refer to
Engine Cranks but Does Not Run (SI Document ID #834631). If the above diagnosis procedure leads you to a low
fuel pressure condition with a Flexible Fuel (L59) Engine, the most likely cause is a restricted fuel strainer. Continue
with step 2.
•If the vehicle does not have fuel in the fuel tank and the fuel gauge reads above empty, refer to Fuel Gage Inaccurate
or Inoperative (Single Tank) (SI Document ID #850196). If the diagnosis procedure leads you to a faulty fuel level
sensor, the most likely cause is a contaminated fuel level sensor. Continue step 2.
2. Check the vehicle's repair history.
•If the vehicle has NO history of the fuel sender / module assembly replacement, replace the Fuel Level Sensor Kit
AND the Fuel Strainer Kit.
•If the vehicle is experiencing a fuel level sensor issue ONLY and has had the fuel sender / module assembly
replaced with P/N's 10355739 or 10355740 that included a redesigned fuel strainer, replace the fuel level SENSOR
only.
3. Replace the fuel level sensor kit and / or the fuel strainer kit (see the Parts Information below) using the above vehicle
history information. Refer to the applicable SI procedure below:
•Fuel Level Sensor Replacement (5.3L (L59) Engine) (SI Document ID# 1314273)
•Fuel Strainer Replacement (E85) (SI Document ID# 1701019)

Notice: Flush the fuel tank. Failure to flush the fuel tank may result in the fuel strainers becoming restricted again.

4. Flush the fuel tank once the fuel sender / module assembly has been removed. Refer to Fuel System Cleaning (SI
Document ID #802838).

Parts Information
Part Number
Description
19122083
Strainer Kit – Fuel Pump Inlet Strainers with RPO L59
88966958
Sensor Kit, Fuel Level
Tahoe / Yukon (Redesigned Fuel Level Sensor)
with RPO L59
88966959
Sensor Kit, Fuel Level
Suburban / Yukon XL (Redesigned Fuel Level Sensor)
with RPO L59

Warranty Information
Important: Use ONLY the appropriate Labor Operation Code. If replacing both the sensor and strainers, use Labor Operation Code L1198.

For vehicles repaired under warranty, use:
Labor Operation
Description
Labor Time
L1197
Sensor, Fuel Level Sensor (Tank Unit) – Replace
Use published labor operation time
OR
L1198
Filter, Fuel (In-Tank Strainer) – Replace
Use published labor operation time

 

I have a 2007 suburban with flex fuel. My mileage was not that great until I realized a computer board that manages flex fuel was out.
Very expensive part!
I am looking to get an older suburban, but want to get Flex fuel. What year did they start putting flex Fuel in Suburban's?

 

I wouldnt even put that E85 crap in my Lawnmower or Snowblower more or less a
Suburban or Tahoe

 

First, I'm not aware of any small engines that are rated for flex fuel, E85. I started using pure gas in all my small engine lawn equipment a couple of years ago and saw a great improvement in operability.

I conducted an experiment this summer where I used Premium pure gas for a thousand miles. My mileage improved 14% vs only an 8% increase in cost. I only used premium because that was all that was available without any alcohol. All of my mileage figures are hand calculated since the DIC figures run slightly optimistic.

The really sad thing about using ethanol based additive to gasoline is that it takes more energy to produce the ethanol than you recover in your vehicle.

 

I use NON Ethanol Premium in everything i own. yea it costs more but the results are worth it. My 6.0 suburban runs better, my 72 bronco runs better and i can keep it in the snowblower without running a Fuel storage additive and it wont gum up.

 

I find it amusing (and reassuring) that things like 'pure gas' are now common.

10 years ago, it was ALL PURE GAS.

People eat corn and engines eat GAS.

In any case, I'm still saving my pennies...

Model X | Tesla Motors

0-60 under 5 seconds, and I never have to change the oil or stop at a smelly gas station again... I plug it in like my cell phone each night...

I want one like there's no tomorrow... My wife and I have driven the Model S, and are ready to drive the X!

 

So there are 3 grades of gas at most pumps 87, 89 and 93 Octane
I ASSUME that all the 87 contains up to 10%
89 may contain up to 10%
93 contains NO alcohol or is this subject to the station owner?

 

as Ethanol raises the octane rating, I believe you'd be more likely to find more in the higher octanes...

"Where the octane number is raised by blending in ethanol, energy content per volume is reduced. Ethanol BTUs can be compared with gasoline BTUs in heat of combustion tables."

Octane rating - Wikipedia, the free encyclopedia

 

Do you have a part #. How do you know it went bad. Please fill me in. Mine is getiing like 13 mpg avg. but the wife is heavy footed. No she's not heavy. Lol. But she definitely doesn't know how to feather the pedal!!

 

Basically you have to check. Some states don't even require labels on the pumps anymore on ethanol content.

Most, if not all, marinas at the lake carry pure gas since a lot of boats were made before this ethanol travesty was foisted upon us.