Ok, First things first. Truck is a 1999 GMC Sierra w/ 5.3. I am getting a random miss, only code is P0440, it does it sitting at a red light or driving down the road, any where from 45-80 mph. Like I said it does it randomly some days it doesn't do it at all then some days it does it a lot.

things that have been done,
New plugs and wires and check coil packs.
New upgraded injectors and tune.
New fuel filter and new pump,
Had the crank relearn done as well with no luck.
Maf sensor has been cleaned several times.


I'm getting aggravated with this truck I'm tired of throwing money at it.

I know the P0440 is an evap code and i have the part already just have not installed it.

 

Cracked plug and or leaky wire.
Do a water mist test for spark jump.

What plugs and wires are on the engine, model numbers.

 

it was doing this before the plug and wire change.

these are the plugs https://www.summitracing.com/int/par...7397/overview/
these are the wires https://www.summitracing.com/int/par...5574/overview/

 

That is most likely your egr valve id you have no vacuum leaks. Use a can of carb cleaner at idle and spray all over your intake and evap etc esp around gaskets and make sure you dont have an issue there. After that its most likely egr.

 

EGR was deleted when i had the tune done with the injectors. and intake bolts are tight, thought that as well, but gaskets where replaced when i did the knock sensors a year or so ago. would the P0440 code make it run bad, i know its causing me aggravation when pumping gass...lol.


thanks for all the help sofar.

 

If the pump is shutting off while filling up gas tank its the, dangit, cant think of the valve name now.

Its mounted on the frame just next to the gas tank above drive shaft, its like 20$ and vents the gas tank. when it fails it causes the tank to over pressure when filling up, telling the pump that your tank is full thus shutting the pump off. It takes about 10 mins to swap.

 

i have the part, just couldn't get to it with the bed on, would that cause the issues with the miss or what ever it is ?

oh yea truck has 197,680 something miles on it.

 

anymore ideas as to what it could be?

 

would having the cruise control on cause this issue?
like on, but not set?

 

here are fuel trims ans o2 sensors,