Hard to start and runs rough right after gas fillups

flap00

Original poster
Member
Apr 8, 2013
44
I've only had my '06 TB LT EXT for a few weeks. Every time I get gas...which has pretty much been full fills...I turn the key, and it won't start right away, then when it does runs really roughly. This has been at different gas stations, but ones I frequent in other vehicles, so I know it's not an especially poor quality gas. After a little bit of revving, it seems to clear up. Dirty injectors? Something else causing the computer to change something? Any ideas? Thanks! :smile:
 

dmanns67

Member
Apr 3, 2013
32,979
Ohio
Any codes pop up yet? Since your only having the issue after fill ups (And bad gas is not the issue), my best guess would be either Evaporative Emission Canister (EVAP) purge solenoid valve (AC Delco Part No. 214-1680) or the EVAP vent solenoid valve (AC Delco Part No. 25950499). I have personally changed my EVAP vent solenoid valve, cost me $45.00 and about 20 mintues of my time. The purge solenoid valve will run you about $30.00, but from what I have seen it takes more work to swap it out.

When was the last time the fuel filter was changed?
 

CaptainXL

Member
Dec 4, 2011
2,445
The purge valve is likely stuck open and the canister is more than likely full of fuel. Vehicle has probably been "topped off" a lot.
 

flap00

Original poster
Member
Apr 8, 2013
44
Thanks!

Well, I was out today, so I figured I'd stop at Advance Auto Parts to get my codes read. I got a slew of 'em. 8 total...
C0455
C0244
U1016
P0128
P0171
P0300
P0496
P0894

After that, I was passing a Pep Boys, so I decided to see what their code reader had to say. Theirs reiterated only 3 of the 8...
P0171
P0496
P0894

Yikes. Guess I have some work ahead of me...
 

CaptainXL

Member
Dec 4, 2011
2,445
P0496 is for evap flow when not commanded. Usually a new purge or vent solenoid fixes this. This is the reason for your original complaint after filling up.

P0128 -Change the thermostat and coolant temp sensor. Then remove and clean the throttle body. Also replace spark plugs and 02 sensor. Run some fuel injector cleaner. Disconnect the battery for 30 minutes. Then reconnect and drive it for a month or so and scan it again.

P0894 is for transmission slipping. Have transmission serviced, filter and fluid changed. Go from there.
 

CaptainXL

Member
Dec 4, 2011
2,445
For the U1016...

Intermittent Loss Of Communication Several U-Codes and Symptoms
[2006 Buick Rainier
2006 Chevrolet Trailblazer, Trailblazer EXT and Trailblazer SS
2006 GMC Envoy, Envoy XL and Envoy Denali
2006 Saab 97x
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Condition/Concern (http://service.gm.com/servlets/#ss1-1766589[/URL]
<a href=""http://service.gm.com/servlets/#ss1-1766589)

Intermittent Loss Of Communication with several U-Codes and possible symptoms. Most common codes are the U1300, U1301 and U1305, U1016, U1064, U1096, U1169, U1161and U1162. Symptoms are one or all of the following; ABS Light On, Security Light On, Multiple Indicators On in the IPC, Heated Seats inoperative, Drivers and/or Passengers Door Window(s), Lock(s) and Mirror(s) are Inoperative. This concern can be intermittent and at times difficult to diagnosis yet communication is not always lost with the Tech 2. This concern when present, can be cleared by cycling the ignition to the "OFF" position, pause for a moment, then restart the vehicle. This could be the result of a module software concern and only applies to vehicles equipped with Memory seats (AAB), Heated seats (KA1), Electric Pedals (JF4) or a combination of them<a href=""http://service.gm.com/servlets/#ss2-1766589
]

An updated calibration was released for this concern. This calibration only applies to vehicles equipped with Memory seats (AAB), Heated seats (KA1), Electric Pedals (JF4) or a combination of them. The software was released on Monday February 20th 2006 through "TIS-2-WEB". It will be necessary to reprogram the Drivers Door Module (DDM), Passenger Door Module (PDM) and Drivers Seat Module (DSM).
1st - Reprogram the Drivers Door Module (DDM). Use SPS programing procedures and select the calibration that states
New software to address intermittent loss of power mirror, power window, and heated seat functionality which may be temporarily corrected by cycling the ignition".
2nd - Reprogram the Passenger Door Module (PDM). Use SPS programing procedures and select the calibration that states
New software to address intermittent loss of power mirror, power window
3rd - Reprogram the Drivers Seat Module (DSM). Use SPS programing procedures and select the calibration that states...
"New software to address DSM no communication issue during factory testing
Note: Prior to programming the Drivers Seat Module, make sure the LGM/DSM fuse is installed. This will only be a concern if TIS had a message advising to remove LGM/DSM fuse for programming the Drivers or Passengers door module.
If there are programming concerns, the TIS version numbers are listed below. Verify your TIS version numbers as necessary
TIS 2000

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


Basically the vehicle control module needs to be updated by a GM dealer or an independant shop that has the capabilities of doing this.
It appears to be a technical issue but not a recall.
 

triz

Member
Apr 22, 2013
746
CaptainXL said:
P0496 is for evap flow when not commanded. Usually a new purge or vent solenoid fixes this. This is the reason for your original complaint after filling up.

P0128 -Change the thermostat and coolant temp sensor. Then remove and clean the throttle body. Also replace spark plugs and 02 sensor. Run some fuel injector cleaner. Disconnect the battery for 30 minutes. Then reconnect and drive it for a month or so and scan it again.

P0894 is for transmission slipping. Have transmission serviced, filter and fluid changed. Go from there.

That is good advice right there!
 

flap00

Original poster
Member
Apr 8, 2013
44
CaptainXL...Thanks so much, man! Greatly appreciated. Nice to have a course of action, and I shall definitely begin following it. :smile:
 

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