Someone stole gas from me and now my engine runs weird?

[Dustin Jackson]

Hello gentlemen, in the middle of the night on the 4th of July someone stole gas from my Tahoe while it was parked in my driveway. I went to leave for work the next day and discovered my gas cap on my rear tire.

I put the gas cap back on the Tahoe and drove to work. On my way home from work I filled up with 91 at my usual gas station, but ever since then the motor has idled a little rough and on the freeway my Tahoe has a little shimmy like an unbalanced tire or slight misfire.

I just redid my front brakes the day before my gas was stolen so I am going pull my front tires back off and inspect all mating surfaces but I have this paranoid/OCD feeling in the back of my mind that the stealing of the gas caused something to happen with either the EVAP system or they got dirt in my tank. OR the gas station just switched to summer fuel here in California. Either way my motor isn't running as smoothly as it did a few weeks ago.

Today I filled up another tank of gas and the Tahoe had a very notable rough idle immediately after starting it from filling it with gas.

Along with having my property violated! My Tahoe isn't running as well as it used to and I want to see if there is anything I can check on, I am hoping these are just the early stages of a EVAP failure. I have had a history of not being able to fill up the gas tank in one go, the pump always clicks so I have to hold the nozzle at a special angle to get to a full tank.

Lesson learned, locking my Tahoe every night and installing security camera.

Anything you guys can think of or am I just paranoid?

This is how I found my tahoe:

 

[B-train]

That totally sucks. I'm not sure if they would actually be able to get any gas out with a siphon on these trucks, but I've never tried either.

I'd do an inspection underneath to see if they knocked anything loose in their attempt

 

[Dustin Jackson]

That totally sucks. I'm not sure if they would actually be able to get any gas out with a siphon on these trucks, but I've never tried either.

I'd do an inspection underneath to see if they knocked anything loose in their attempt

Is there anything in the fuel filler neck between the tank and the hole that they could of knocked around or damaged?

 

[j91z28d1]

did you notice fuel missing? maybe they put something in the tank messing up your fuel pressure?

 

[intheburbs]

Virtually impossible to steal gas out of the tank.

Much more likely that something was put into the tank.

I'd start with running some good fuel injector cleaner, like BG 44K, and see if that helps. Then, I'd do other "tune-up" items - air filter, spark plugs, etc.

 

[Dustin Jackson]

did you notice fuel missing? maybe they put something in the tank messing up your fuel pressure?

Was already out of gas so and my gas gauge is very lazy so impossible to tell if anything was added or taken away unless it was by the 10s of gallons

 

[Dustin Jackson]

Virtually impossible to steal gas out of the tank.

Much more likely that something was put into the tank.

I'd start with running some good fuel injector cleaner, like BG 44K, and see if that helps. Then, I'd do other "tune-up" items - air filter, spark plugs, etc.

I’ll try some fuel injector cleaner or sea foam. No need to replace those other parts, the motor was halfway rebuilt last summer and ran perfectly fine as recent as I can remember. I pay very close attention to my truck any time I drive it

 

[B-train]

Is there anything in the fuel filler neck between the tank and the hole that they could of knocked around or damaged?

I don't think so, unless they went underneath and messed with the vent or something. I was under the impression that most new tanks had some sort of blocking device that prevented siphoning.

After reading further, I would agree that something was PUT into the tank. Maybe sugar, piss, etc. People are idiots.....

 

[OR VietVet]

Any CEL? You already knew you had evap system problems? My guess is that they tried, could not get fuel and dumped something in there but maybe damaged this too:

More Information for SPECTRA PREMIUM FN779

If you do the try to address the evap system do the entire system. If they dumped something, it could be in the entire system. Sucks.

IMO, if I caught someone doing that, pulling fuel out or dumping something in....I will hurt them.....badly. I need to work on my bat swing anyway.

 

[Dustin Jackson]

@OR VietVet No check engine lights and yes I had pre-existing fuel filling problems.

I inspecting under the Tahoe near the filling neck and nothing was tampered with. The Tahoe was completely unlocked but it doesn't look like they opened the doors because all my stuff was inside. I am hoping they just attempted to steal gas and left empty handed but here we are

If something was dumped down the filler neck would it go straight to the tank or would it hit the EVAP system first?