Truck bogs down after starting and taking off.

[Ak101guy2024]

Hey everyone, I have a 98 K1500 Chevy with the 5.7 vortec and automatic transmission. I have noticed lately that if I start my truck and immediately take off it initially bogs down and acts like it wants to stall. This happens regardless if it was previously running or not as it happened when I stopped for gas today. I am wondering if it is the spider injector it has over 300k on what I am guessing is the original unit. The engine is a new jegs crate motor with a little over 20k. I just swapped the intake over. No gas leaks into the oil as far as I am aware. Been looking at possibly upgrading it with a mpi unit if the oem one is bad. Thanks

 

[Road Trip]

Hey everyone, I have a 98 K1500 Chevy with the 5.7 vortec and automatic transmission. I have noticed lately that if I start my truck and immediately take off it initially bogs down and acts like it wants to stall. This happens regardless if it was previously running or not as it happened when I stopped for gas today.

Greetings Ak101guy2024,

Welcome to the GMT400 forum. In order to get the talent interested in your issue,
let's see if we can unearth any symptoms that might remind them of something they
experienced/solved on their vehicle:

Q1: Is this an intermittent issue, or can you reproduce the just-started bogging at will?
Q2: Does this primarily happen stone cold, or does it primarily occur hot? Or does engine
temperature not make a difference?
Q3: How long has it been since you replaced the fuel filter? (Thinking slow pressure rise,
and suddenly taking off the engine gets ahead of the climbing fuel pressure?)
Q4: How long has it been since you've added a Techron-type fuel system cleaner to the tank?
Q5: Describe exactly how you would drive the vehicle in order to avoid this bogging?
Q6: Is the SES light lit? Any stored codes? (The 'C' class codes will be stored but *not*
light the SES light.)
Q7: Have you ever checked the fuel pressure to see if it is within factory specification?
Q8: Has it ever run correctly for you in the past? If so, can you remember anything
that happened to the truck around the time that this bogging started occurring?

****

At this point you would follow Schurkey's advice to make sure all the consumables are in
good condition. (Ignition / Tune up items)

If the problem persists, then we will need some live data in order to figure this out. For
example, does the problem only occur Open Loop, and once everything is back up to operating
temp and we go into Closed Loop the computer has tuned around the root cause? If the problem
persists in Closed Loop, then we can look at the state of the fuel trims for some clues. (For example,
large positive fuel trims during light loads = possible intake manifold leak that's worsening?
Or large negative trims are due to uncontrolled fuel escaping from the spider assy?)

****

If you could answer the above questions if might give us a hint about what's going on.

 

[Ak101guy2024]

To answer your questions the issue is consistent but can sometimes not occur, I usually have to let it sit for 30-60 seconds and it won’t do it. 2 it happens both cold and hot. 3 Filter was new when I got it 2 years ago I have meant to change it, 4 I have not added any fuel additives ever, 5 there is no way to drive to avoid the bogging I can drive extremely slow after starting and it won’t do it as bad but you can still feel it stuttering, 6 there are no lights at all or code appearing, 7 I have never checked fuel pressure, 8 it ran correctly with the old engine and the new one at first for the first 10k miles I believe. I appreciate the reply, and I am planning on changing the fuel filter at some point.