2009 5.3L stalls when warm

Berk Taylor · April 27, 2016

Over last couple of months my 2009 Silverado 5.3L stalls once it's warm...meaning the first time I start it for the day it starts right up. But after it is driven 10-15 minutes and you make a stop, the next time you fire it up, it stalls as soon as it catches fire. 7-8 times in a row. Even trying to use the accelerator to keep it running proves tough unless you really gun it, which I don't like doing in even oil pressure isn't high enough.

This truck I bought new and it mostly sits in my driveway during the week and is used on weekends for hauling a boat, motorcycles or doing yard work. It has about 23k miles on it and is well maintained.

I am wondering if it has EFI buildup from all the ethanol in the gas these days that plague smaller motors, or if it has some moisture in the system somewhere.

Any ideas would be appreciated before I send it to the dealer to be looked at.

bubbanbrenda · April 28, 2016

I had similar symptoms, do you have any codes? Mine was the fuel pump control module above the spare tire, very poor design.

http://brianearly.blogspot.com/2014/01/jackass-award-gm-pickups-fuel-pump.html

Excellent explanation in link above.

Berk Taylor · May 5, 2016

Thanks for your reply...as it turns out it was an odd situation. It wasn't throwing a code, so I ended up taking it into my dealer to see if they could get a code out of it. There were too many possibilites, so i didn't want to spend tons of time chasing the issue. They suggested a wireless transponder on my keychain was causing the issue. This transponder is one that is becoming common. What it is: storage units and parking garages are starting to use these little disks that go on a keyring so that you can gain entry/exit by just rolling up to the facility and the gate opens. For some reason it was either sending a signal on a frequency that my ECU uses or somehow interfering between the ignition key chip and the ECU. They had me remove the transponder from the keychain and instructed me to leave it at home. They also wanted me to buy a new key to in event this had corrupted the chip on my key. I elected to not get a new key, but just remove the transponder first. Problem solved. Not one incident since this occurred. Incidentally the day I took the truck in to find out what was going on, it began to have problems on initial startup, not just when warm. This is what led me to go ahead and take it into the dealer.

So now I have another dilemma. How do I use my transponder on the rare situations I need to go to storage? I have 2 options. 1) just take transponder with me on days I plan to go there and deal with it possibly causing my truck issues on that day. I don't like this idea, because of not knowing if it may cause long term damage to the ECU as well as sometimes you may forget to take the transponder with you and that would be a 36 mile wasted roundtrip.

2) Buy a RFID wallet (one of those new metal wallets that make it harder for a RFID scanner to steal your credit card into, which I have two of both completely full of credit cards and Costco cards so I would be making a separate purchase just for this stupid situaion). I don't know that the transponder will keep it from interfering with my ECU so it may be a waste of money. Also it may need to be opened at the entry/exit of my storage unit for the gate to open. I think I may try this as the only other option is to change storage units, which in the Seattle area would be way too expensive to entertain. A 20x10' unit goes for $300-$400/month and I found a steal 18 miles north for $155.

I have pased this info on to the storage unit in event that other customers complain. It may only be mine that has this issue since the manager hasn't heard of another customer having complaints. It may just be a frequency issue between my truck and my transponder rather than a general issue between transponders and ECUs.

Thanks again for the reply.