how do i tell what's causing my car to run rich?

[VRCALAIS.]

hey guys i'm all the way from australia,my question is how do i tell via the dash what is causing my car to run rich i'm currently using efilive v4 on my 1994 holden vr calais running a n/a series2 buick 3800 v6.the thing keeps missing,backfiring, running rich it doesn't throw any error codes either i'm thinking a vacuum leak but just want to see if i can confirm it with efilive as i've been trying to fix it for the last 3 weeks with no luck an i'm about to burn the damn car...any way here's a screen dump of the car at idle

http://i43.tinypic.com/do8ems.png

can i do something similar to this?
"Plug your scan tool into the diagnostic connector and start the engine, then look at the Short Term Fuel Trim (STFT) and Long Term Fuel Trim (LTFT) values. Normal range is typically plus or minus 8. If the numbers are +10 or higher for STFT and LTFT, the engine is running LEAN."
http://www.aa1car.com/library/problem_hesitation.htm

[joecar]

Can you show the chart of that...

[VRCALAIS.]

Can you show the chart of that...

http://i42.tinypic.com/b821ee.png

[joecar]

Does it generally run rich or does it run rich in a specific situation...?

Did it just start happening or did it always do it...?

The chart shows revving the engine with car parked... the O2 sensor shows it being very rich... do you have a log of driving on the street showing it going into closed loop...?

Did you check your rail pressure (is it too high) or for leaky injectors...?

[VRCALAIS.]

Does it generally run rich or does it run rich in a specific situation...?

Did it just start happening or did it always do it...?

The chart shows revving the engine with car parked... the O2 sensor shows it being very rich... do you have a log of driving on the street showing it going into closed loop...?

Did you check your rail pressure (is it too high) or for leaky injectors...?


it's been running rich for a while by looking at the spark plugs,i was running vt injectors in it which were a different pressure (3.5bar)so i went back to the stock series 2 injectors (3.0bar),changed the oxygen sensor a couple of weeks ago an cas,it always runs rich only recently it's started missing aswell.i don't have a log file as of yet.

[VRCALAIS.]

i have screen shot now an a log file if any one can take a look?
http://i44.tinypic.com/344pgls.png