GMC Truck Forum banner

1 - 8 of 8 Posts

·
Premium Member
Joined
·
2,287 Posts
Discussion Starter · #1 ·
So I recently bought a NBS 2000 Silverado 4.3, 5 speed, 4x4.

It ran like crap when I got it so I figured, hey a tuneup will fix it. Nope, still runs bad.

Runs bad: 95% of the time, Extrelemy slow acceleration, 5% of the time, runs like a TT Z28 :crazy:.

When its running bad, It will "surge" randomly during acceleration as well as have almost no power.

Parts I've replaced in the past month:
MPFI conversion
Fuel pump
Plugs, wires, coil
Distriutor
cats gutted
fuel filter
air filter
cleaned MAF, MAP, and EGR (may do EGR again)
Sea foam in the intake & fuel tank

Before you say its a slow V6, at least provide a little help :head3:
 

·
Registered
Joined
·
449 Posts
How many miles it got on it might help to know? And like it in decent shape or been kinda roughed up in it's life?
 

·
Registered
Joined
·
370 Posts
It's missing 2 cylinders.
 

·
Registered
Joined
·
419 Posts
yes you cleaned the maf , but it still may be bad.
 

·
woo
Joined
·
218 Posts
Are you using the AC? Mine surges when the compressor unlocks from spinning lol. Check engine light on?
 

·
Premium Member
Joined
·
2,287 Posts
Discussion Starter · #6 ·
How many miles it got on it might help to know? And like it in decent shape or been kinda roughed up in it's life?
165k, and idk about its past life. I got it a couple months ago.

It's missing 2 cylinders.
Thanks, you're a fucking genius. :bird:

yes you cleaned the maf , but it still may be bad.
I forgot to ad that i tried a new MAP and MAF for about 3 miles, no changes.

Are you using the AC? Mine surges when the compressor unlocks from spinning lol. Check engine light on?
I had thought about that, except doesn't the AC cut out at WOT? The truck surges there too.
 

·
woo
Joined
·
218 Posts
I'm not sure if it does on these. Last week towing my camper I thought I felt it lock/unlock going up a few grades. Granted I wasn't maxed out but, it was spinning at ~4k.
 

·
Registered
Joined
·
449 Posts
Hmm now knowing the previous history is not good, it's probably been driven hard to be this worn out, mines a 1999nbs 4.3 with around 146k but it runs solid for a 4.3 minus the trans is messing up, but you've not got that issue, tire size might be some of the problem?? What size tires you running? And this may sound kinda funny but find someone else who has a 4.3(that you knows in good running order) and drive it maybe or ride in it to compare, cause yeah 4.3 does act "rough" as in slow to get up and go and with air conditioning on it takes a little more time on mine to get to 4k rpms, so it might just be where your not used to the lack of power
 
1 - 8 of 8 Posts
Top