here WE go... I was reading the post abouth "Fuel trims, what do these #s mean? " and Since I have been Having issues with the same Subject I decited to get a Scanner Its a OTC Monitor 4000 enhancer.
Let me start By Giving the Most Info on My tahoe. 96 L31 Whipple supercharged 5psi boost axuliar injectors, Crower cam 00401LM AC delcos Plugs , I get the codes 1345 at start up almosst all the Time and P0134, headers Glow...Lean? jeez what Else...Let get to the Numbers..

Driving I get this.
HO2S B1 S1 208 moves to 190 mV
H02S B1 S3 933 moves to 924 mV
LONG FT B1 19% moves to 23%
FT CEL BK1 17
SHORT FT B1 50%
O2 XCNT B1 0

HO2S B2 S1 73 moves to837 mV
HO2S B2 S2 438 moves to 442 mV
LONG FT B2 2.33% goes Negative at WOT -14
FT CEL BK2 17
SHORT FT B2 goes minus -1.7 , 0.0, .78%
02 XCNT B2 2 goes to 7

MAF 10 g/s
A/F 14.7 :1
B1 Lean
B2 Rich
Ignition Voltage 12.7V

FP is 52-53psi Idle and at WOT 62-63psi
It has a Rugh iddle the rpms go up down Vac leak?
I have also replase both o2 sensors and the same problem persist same numbers and the AF indicator indicates lean then after a ride it goes to stoich but with the numbers im presentin here It does not Go to Full stoich just a cuple of led lights
Any input, please Help any suggestiong Will be consider
Gilbert.

Gilbert,

The first thing you must fix is your timing.

The camshaft may be a tooth off, I think we talked about that before. Since you have said your headers are glowing this is most likely where the biggest problem lies. Checking that is unfortunately pulling timing cover off and having a real look.

After that you have to make sure the distributor is clocked right. It's definately not in sync with the crankshaft sensor.

Timing must be perfect before you can even begin to think about fuel.

As far as the two trim being the opposite of each other, look for exhaust leaks. Even a tiny exhaust leak forward of the sensor will screw EVERYTHING up.

Do this other numbers mean anything
MAP 60 Kpa
EGR .78V
spark andvance 18.6
Cam Ret 25*

You are taking reading from a scan tool, but I believe mechanical problems need to be fixed first.

Gilbert, I had a similar problem on my truck on the initial startup after the rebuild, I had the headers glow also, My main problem was that we had installed an adjustable FP regulator & had the FP near 80 on idle, & the poppets were bleeding their hearts out. That with the timing off let raw gas get pushed through the heads straight into the header where it ignited from the heat in the header. James is dead on, you need to get your timing correct then address fuel concerns. These Vortecs have to have a crank /cam shaft learn procedure done to get the timing where it should be. This is a very narrow window on the dist. I have seen cases where guys have changed Dist caps & had there timing change 1-2 deg. You want yours set to "0", most guys get them to some where in the -2 to +2 range and thats good enough, shoot for 0. Some trucks are more difficult than others. You can try the crank / cam re-learn procedure 1st, if you cant get your timing correct then your going to need to physically check your cam timing to make sure your not a tooth off.

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