Engine bogging down at lower RPMs

[juf]

Does anyone else's engine seem to bog down at lower RPMs? Many times when accelerating it's as if the engine is choking on itself then catches up once a higher RPM is reached.

 

Another funny thing is when driving slowly up a steep incline. The truck seems to stay in 2nd or 3rd gear until it almost stalls. I'll press the pedal in a good one to two inches before it downshifts to first gear at 4k RPM. Seems like a 5.3l should have enough power to drive up a hill without downshifting to first to avoid stalling.

 

Possible fuel pressure problem?

[fondupot]

what gears does your truck have? if its the 3.08's its gonna take a bit of push on that skinny pedal to get her moving.

[juf]

I have the 3.42 gears.

[klrrdr]

Silly JUF, these trucks were not designed to go up hills.

[juf]

Ha that's what it seems like! My 08 Sierra had an easier time accelerating and going up steep hills.

[jcastyo]

Does anyone else's engine seem to bog down at lower RPMs? Many times when accelerating it's as if the engine is choking on itself then catches up once a higher RPM is reached. Another funny thing is when driving slowly up a steep incline. The truck seems to stay in 2nd or 3rd gear until it almost stalls. I'll press the pedal in a good one to two inches before it downshifts to first gear at 4k RPM. Seems like a 5.3l should have enough power to drive up a hill without downshifting to first to avoid stalling. Possible fuel pressure problem?

I have the same issue and was wanting to know as well with the bogging down/hesitation at lower rpm's. I also have the 3.42 gears. Can't comment on going up a hill, it is all flat land here. I think I remember having this on my 2005 GTO, wonder if it has to do with the throttle being electric instead of a cable?? Would a tune take care of this problem?

Edited March 4, 2014 by jcastyo

[fondupot]

my 5.3 and the 3.42 gears gets up hills no problem. You just gotta get into the skinny pedal a bit more compared to your 08 with a 4 speed trans. The 6 speed trans needs more throttle to downshift. Don't be afraid to rev the engine up...that's what they are made for.

Edited March 4, 2014 by fondupot

[juf]

I HAVE to push the pedal down to get it up the hill. Just seems a little ridiculous to downshift to first gear at 4k RPM to make it up when an older vehicle cruised up no problem.

[20L8TSierra24]

Under light acceleration, the truck will remain in V4 mode and almost feel like its bogging. Mine does it as well and i just push the gas a little more and you can watch it go into V8 and feel it light up right away. Just put a little lead in your foot lol.

[66nova]

Black bear tune will cure that problem.

[juf]

Disclaimer: my 08 was blackbear tuned. Might have spoiled me a little. Too paranoid to tune the new truck because of warranty though.

[scott19677]

Combo of Variable Valve Timing, V4, 6 speed. Mine does the same thing. Sometimes at low speed , stomp the gas pedal and NOTHING. Like a deer in the headlights for a second or two.

[pm26]

This is why I like manual transmissions. I currently have one in the 2013 Chevy Sonic. Although I have no complaints about the 4 speed auto transmission behavior either in my Silverado or Impala LTZ. Impala especially is very quick to downshift when you push on the gas pedal even slightly. Silverado requires slightly heavier throttle to downshift but then the non-AFM 5.3 has a lot more torque than the 3.9 liter V6 in my Impala so it can run at lower RPMs in the fourth gear without feeling too strained.

 

I believe that GM in their effort to maximize the fuel economy has pushed things too far on these new trucks and maybe some aftermarket tuning can fix it? We have a 2012 Silverado crew cab 4X4 with the 5.3 AFM engine/6 speed auto at work and I do not find any issues with the transmission shifting. I cannot tell when it is switching between 4 and 8 cylinders either.

Edited April 22, 2014 by pm26

[redwngr]

I HAVE to push the pedal down to get it up the hill. Just seems a little ridiculous to downshift to first gear at 4k RPM to make it up when an older vehicle cruised up no problem.

Do you still have this problem?

Did you take it in?

Did you figure out a way to encourage to downshift but not all the way to first (or whatever gear is resulting in 4000).

[juf]

Yeah, still have the problem. Took it in to dealership twice, but they aren't any help. They just say there's no codes, and won't look into it further. Seems almost like a fuel pressure problem or spark problem, but I don't have the means or know how to check it out myself.

 

I did get a diablosport tuner, and the canned tune seems to help. Just started the process for a custom tune from Lew.

 

I did do a log file and noticed the fuel pressure drops when first accelerating. Does anyone know if this is normal?