Hi all!

I’ve got a 2011 Chevrolet Silverado 1500 WT, Reg can with the 4.8 V8.

Last year, the truck was idling rough, would almost stall then rev back up again.

I replaced all spark plugs, and wires and was still doing it.

i then replaced the TPS then it was fine (over on mileage for TSB warranty unfortunately).

Anyways for the last few weeks it started idling rough again, and would almost stall out then rev up (only when idling) and would have to turn over a little longer to start.

Last night, it was getting cold and I went to start the truck but wouldn’t go - cranks over fine but does not fire up so I thought maybe water in fuel.

However I let it sit overnight, as it got colder then the next morning it started fine in -010c

I am waiting for the fuel pressure gauge to come in to check that, but for now I checked the fuel control module that is located near the spare and I am getting the 12V there - the green white, and the pink one as well as the main.

I also jumped the wires to manually start the fuel pump, which I heard it go on but sounded a little loud and high pitched, which could be normal?

The only code I have that shows on my cheap scanner is for an EVAP leak.


I got a subscription to alldatadiy but it isn’t friendly enough for me to take advantage of.

Does anyone have a set of procedures that I can follow to help diagnose this - that is if I’m getting proper pressure but still does not want to start?

Thank you kindly for your time,

Sylvain

 

While waiting for the fuel pressure gauge, I would try cleaning the throttle body to see if that helps any. Also look for any vacuum leaks.

 

I can try cleaning it but I did just do it last year. Fuel pressure gauge that came in doesn’t have proper fitting so I will have to wait until tomorrow to figure something out.

 

It could be the fuel pump. Normally they make a whine at start up be it goes away after you start it. I'd put a new fuel filter on it regardless, unless its fairly new.

 

I am still waiting on a fuel pressure gauge but in the meantime what do you think of this:

Its the third time now when it sits overnight it starts in the morning. I turn it off, then immediately try to start it again and it just cranks over and that’s it.

I pulled a plug to check for spark, and when I pulled the plug out it was wet and full of fuel, and even dripped a bit on the fender...

Spark is really good, even in the sun I can see it no problems.

Also, I thought this was just a carburetor thing but if I hammer down on the throttle it’s fights to fire up then fires up, and if I keep the revs at 2000 for around 10 seconds it will place itself and idle fine..