5.3 Check engine light??

[Beatdown Z]

I'm facing the same problem right now. I just replaced my plugs wires are on the way to me. Going to chang my fuel filter and get some injector cleaner and see what happens. I have spare coils packs so I just might change them as well and see what happens.

Does your truck idle real rough/surge when you start it up on these cold mornings?

[eallanboggs]

You should monitor your STFTs while you spray the fluid. The STFTs will react even if you can't hear a change in idle speed. You can also read the Freeze Frame data for your DTC. It will tell you the parameters that existed when the DTC went set. You can try duplicating those conditions and then spray the fluid unless it only happens at 60MPH which won't too easy to repeat.

[Beatdown Z]

Intake gasket leaks are very hard to detect on these engines. What makes it difficult is that they only leak when the engine is really cold, upon initial startup. Once the engine begins to warm up, things expand and the gaskets seal themselves.

[txarkitekt]

You should monitor your STFTs while you spray the fluid. The STFTs will react even if you can't hear a change in idle speed. You can also read the Freeze Frame data for your DTC. It will tell you the parameters that existed when the DTC went set...

Damn man, good call. Words from someone that sounds like you know what you are talking about! You need to make more posts!!!

...You can try duplicating those conditions and then spray the fluid unless it only happens at 60MPH which won't too easy to repeat.

So you are saying that popping your hood and climbing out to spray carb cleaner on the intake gaskets at 60 MPH would be a tough thing to do?????

[Chevytruck]

Does your truck idle real rough/surge when you start it up on these cold mornings?

Ah not really. We watched the firing the other day and all cylinders were missing at idle but not when I held it at 3K RPM.

Not trying to jack your thread buddy, just that I am going threw the same exact thing that you are and maybe we are having the same problem and we can both get out trucks fixed from the help of the site.

[Chevytruck]

Ran a bottel of Lucas injector cleaner (1 qt.) with 1/8 tank of gas and the code went off on it's own.

[Chevytruck]

Light is back on again....

[the boy]

allright well im gonna try putting in a new O2 sensor on the driver side saturday, i'll let ya know if that makes any difference. and yes my truck idles rough and sometimes kindof chokes when im driving but if i put it in neutral rev it a bit it works better..

[the boy]

Put the new O2 sensor in today cleared my codes, and drove the truck most of the day and the light didn't come back on. Also the truck ran good the whole time, didn't sputer or anything. hopefully that fixed it.

[GT killer]

I just had pretty much the same problem, i was coming home the other day and all of a sudden she starts sounding like a cammed out big block and the light started flashing (its been on since i holowed out my cats throwing cat efficency codes ) pulled the codes and found p0300 random missfire and p0174 system lean bank 2. No sign of any 02 codes but did like ya'll said and changed mine out and took care of it. Although the comments about the intake gaskets got me doing some research and found out felpro makes a new upgraded intake gasket set with a metal frame and rubber inserts part # MS 98016 T for my 5.3 i really like the new design seems a hell of alot more stout im working on doing a tread on replacing them when i get the time. Sorry not tryin to jack anybodys tread just hope it helps someone.