Ok, I have a 2004 Chevy Silverardo, 1500, Z71 5.3 engine. I have always put premium gas in my truck. Well, I stop at a gas station and the gas station didn't have any premium, so I put the cheap gas. Well a few miles into the road and my service engine light turned on and I knew it was the gas. I had read about using cheap gas will make the engine service light turn on.

So I don't fuel up again until it's almost empty. I let the fuel light come on telling me low fuel, and go fill it up with premium gas. I like chevron or mobile, so the next day, wake up and I get into my truck and the light is gone. Cool! This happened over a year and a half ago.

So, about 3 weeks ago, I fill up at this piece of **** gas station, had a beat up sign of Texaco and fill up with premium. A few miles later, service engine light turns on, and I was like, ****, I bet that was not premium gas. Do the same as before and the light remained on. I diconnect the battery to reset the computer, 2 hours later, and the engine service light turned on. I was like, "dam, something is wrong". Drive another week like that, take it to the dealership for the reading and they told me it was the knock sensor.

They told me it costs $39.95, but they would have to order. I was like, OK, i'll be back. Well this morning, the light is gone?!?!?

Should I go ahead and change it? By the way, the engine has two of them. Is it hard to get to them to change them myself?

 

They should not be to hard to get to. Of course you have to remeber that you do have a lot of electronics and other stuff in your engine bay to get around. Too. See what they look like and see if you can find them or even have a mech at the dealership show you where they are.
Even if your light went off I would replace them. If they get bad your pickup will run very poorly.

 

The light turned back on. i will replace them. I hate to see it on, i also hate it when people get in and say, "why is ur check engine light on?" they make it seem like you don't take care of your truck.