well i put new o2s in it and it runs a whole lot better but at idle its still hesitating and sputtering? i found this link and this guy had the exact same problem and his ended up being a bad fuel pump which would effect the whole engine like you said... btw i replaced my pump with a walbro 255 a few months back but maybe its going bad and i should just put a stock one in? https://www.performancetrucks.net/fo...ght=sputtering

 

What ever posessed you to put a walbro unit in? Did you need it? Certainly 44lb/hr inkjectors work fine on a stock pump. Get that chinese piece of crap out of these and get a genuine delphi pump. I think you'll be pleasantly surprised. First things first though, get a fuel pressure guage, hook it up, tape it to the windsheild so you can see it while driving and watch the pressure as you lay into the throttle. I bet you see a substantial drop when driving or under any kind of load.

 

everyone was doing it.... no seriously the stock one was whinning and about to go out so i found a walbro 255 for like $90 and everything i read on here people were saying their a good upgrade, but i'm beginning to think some stock parts are better

 

You'll find very few aftermarket parts that will exceed the quality of gm parts. Only parts in or on my engine that aren't GM original replacements parts are the camshaft, pushrods and valve springs.

 

Agreed for the most part. Generally Sensors, o-ring seals for gas tanks, distributor caps and a few other items are best from the OEM's. Don't hesitate to search out that part number on the web...there are many off-dealerships that sell at cost pricing.

Did you replace the O2's with Delco ?

Bosch are only good for around 30K miles...and then they recommend replacing them.

I know its too late now....but if they flake out again... you'll know.

 

I wasn't in a position to shop around. I got 250miles to that tank of gas in 2 days and the missing and stuttering was killing me. But thanks for the info, I'll make sure I find some Delco's when this one goes out.

My dad popped my hood and seen the battery was ACDELCO and was amazed that I still had the factory battery. I think its a 4 year battery and i'm on year 5.

 

My fuel pump whined a lot when I got it. I started getting gas at 711 (up to 10% eth) and it eventually stopped whining. I'ma chaulk that one up as a win.

 

I hear ya. I have the same problem here. If nothing else, around 40K miles, shop online for one and have it handy.
It should last more than 40K..but like everything these days...

Delco batteries are generally pretty good. But, being your in year 5... carry a pair of jumper cables with you, and save up a bit of cash and tuck it in the glovebox, especially with winter coming.

 

your truck is rich. to have fuel trims like you do you need to lean out the motor. if you went from headers to manifolds then you are rich. when you go from manifolds to headers you run lean. its just the opposite

have someone play with your VE table for little bit of time and be done

popping and sputtering is direct relation of overly rich

 

I always carry jumpers and the battery shows 0 signs of weakening, but I try to keep enough money in the bank to fix anything that breaks.

He's tuned for every mod he has. How would he just all the sudden go rich out of the blue?