garretthes

A little history:
LM7 Engine transplanted from a wrecked 2004 silverado. The engine wasn't damaged but a couple of plugs were snapped off and one exhaust manifold bolt stripped out.
The engine is running the stock 4L60e with stock reprogramed PCM and modified harness.
It runs great until you get on it hard. Sometimes it bogs a little then picks up power as it gets into the higher rpm's. If you run it between wot and 3/4 throttle from a stop, it will run so-so until approx. 4000 rpm then stumble and then pull on until it shifts. The engine is throwing one code only. Lean bank1. I'm pretty sure this is a leaky intake when cold.
Sure could use some help here. I have driven a stock 5.3 and I know this one is not right. I'm getting 20mpg on the highway but the power isn't there.

99huggerorangeZ

iTrader: (2)

mass air flow?

ls1nova71

iTrader: (4)

Has it always done this, or is it a new problem? What kind of fuel pump are you running? In tank or external? Have you put a fuel pressure gauge on it?

garretthes

It has always done it. In line pump. Plenty of fuel pressure. Nice Nova!

TXjeepTJ

iTrader: (8)

mine did something very simular, it was a barely loose ground cable to the engine block. when the engine demanded more power to supply to coils/etc it would start bogging since the ground wasn't 100%

Pop N Wood

iTrader: (1)

This could be anything. Stuck injector, bad O2 sensor, dirty throttle body, vacuum leak, exhaust leak.

AGB1976

Check the mass air flow sensor. Get some of the cleaner form the parts store thats for maf sensors. If it runs any better than before the maf is probably bad. I had this happen to my 2000 ss a few years back.

Petraszewsky

iTrader: (28)

O2 sensors , MAF..... Do you have a way to log your data?

garretthes

I have a basic scanner that will freeze data. That's all. Going to try cleaning the MAF this morning.