I got bad gas,it's been flushed, premium has been put in,fuel injector cleaner added,as well as a water remover. It's still throwing the stabilitrak light,and shifting hard. I'm hoping it's just working itself out. Anyone have this issue?!

 

How many tanks of good gas have you put in so far? If you're just starting with the first tank of good gas, give it time. It make take a couple takes or so to get things back to normal.

 

I just got it back today, so this is the first tank. Thank you, I kind of figured it would take time. But,my first thought was it had screwed up the computer system. And I'd have to spend even more money on it !

 

Does it run well other than the messages and hard shift?

Aside from residual liquid contaminates in the system, the computer may have mistakenly calculated ethanol content while burning the bad gas. There's no ethanol sensor or anything. It's all calculated when the vehicle detects a rise in fuel in the tank and takes information from the evap system and fuel trim numbers. The gas goes straight from the tank through the fuel pump into the fuel rail feeding the injectors. The fuel filter should have stopped any solid contaminates. Water and other liquids would make it through.

A similar thing can happen when you have an almost empty tank of gasoline then switch to e85 or vice versa.

I've heard mention that the rapid expansion of water into a vapor at the tip of a fuel injector can damage it but since the injectors aren't inside the combustion chamber, I can't see how that could even be possible.

Things to do if the problem doesn't go away:

Monitor for misfires. Torque pro with an inexpensive ELM327 device will do it no problem.

Make sure all hoses are hooked up under the hood. It's possible that while working on clearing the bad gas that something didn't get hooked back up properly.

A bad throttle position sensor on the throttle body can also cause this. Very common on a 2007 5.3L.

 

Yes,it's running great besides the messages, and hard shifting,the check engine light is also on.The throttle body sensor was replaced a year or two ago. I just got it back today.

 

Now,it's throwing P0175 code. Will this clear up on it's own or do I need to have it reprogrammed or something ?

 

There's no reprogramming to be done. This could be a bad or dirty MAF sensor but if they removed the intake manifold and other components on the engine to get to the fuel rail and injectors to clean then, there could now be a vacuum leak somewhere. There's a little tube that connects on the back left side of the intake pipe before it goes into the throttle body that I always forget to plug back up when working on mine. Something simple like that could cause this. There could be clamp that wasn't tightened down. They may have reused a gasket or installed a bad gasket that's leaking air into the engine.

Here's a good video on diagnosing P0174 and P0175 codes. Skip ahead to 11 minutes if you want where he discusses how to detect a leak and how to monitor the fuel trim readings to show when you've found it.

 

They changed the manifold gasket, before they realized the whole issue was bad gas. Wouldn't that mean they cleaned everything ?

 

How do you know it was bad gas?

 

As soon as I filled it up and started it, it started acting up I had to be towed to the shop. They said I needed a tune up, and manifold gasket. They did that then said I needed a new catalytic converter. My dad had a friend who restores old cars for a hobby. He replaced the catalytic converter, and discovered there was water in the tank.