tooblue

Need some help or advice. Please

Caprice on a test run (now has posi)
No one lives in the houses on this street (homes still under construction )

I put a 6.0 LQ4 in my 1995 Caprice and it actually runs very well ! Though I seem to be having some slight driveability issues. I notice that (while monitoring with AutoXray) the fuel trim levels seem to vary from time to time while motor is at a consistant RPM /speed. Example: while cruising at 30mph the trim level will go from (0 to 3 to -3) When this happens the car tends to start sputtering and peformance seems to suffer. I have a idea of some things to check But I am looking for some advice :
Possible vaccum leak(s)
Possible exhaust leak,
O2 connections (using aftermarket)
Change O2's to C5 rear 02's

This is a conversion and I know it could be anything but this is the list of parts on the motor

2002 Lq4
Tr224 114
Pacesetter LT's
LS6 manifold
Stock-screened MAF
85mm-BBK throttle body

Sorry for the long post,, Roger

Chris81

iTrader: (1)

Are your o2's switching ok? You might try the C5 rears if not. Voltage (milivolts) on the o2's ok? (too low or high and NOT switching?) Your o2's wouldn't look like sine waves on the scanner if this is happening.

I've seen his do something similar on a friends car.. his LTFTs would jump around cruising when the o2's wouldn't switch right or when one was old and lazy or damaged.. it would add/subtract fuel randomly. But, his would go from -10 to +25.. lol

tooblue

Chris81,, Thanks I will go ahead and switch the O2's (Since I have them already) and see what happens. Roger,,