george 88gta

iTrader: (1)

Car is a 1988 GTA, freshly rebuilt ( bottom to top) 305. All stock except for a 1993 LT1 cam, no big deal. Here is the problem. I hook up my Snap-on mt2500 scanner to check out why it is running a bit rough. Following are the readings after closed loop and up to operating temperature:

desired idle 750
actual idle 800-850
IAC count 6
maf airflow 6
blm 156
integrator 128
rich/lean stays on lean
21 inches of vacumn ( steady)
fuel pressure vacumn attached - 35 psi vacumn removed - 42 psi
tps 0.56
oxygen sensor voltage stays low, less than 80mv
oxygen sensor count stays at 0

Pulled the plugs and they are a bit on the light color side, but have the black mark where the fuel sprays in. The injectors are new BOSCH III 19 lb injectors. I swapped out the MAF sensor with a know good one, no change. I pulled the oxygen sensor and it was dark/carboned at the base and a light grey at the tip. Since I had it out I replaced it with a new NGK 21002. I havent found any leaks around the intake rubber pipes. Tomorrow I plan to pressurize the intake and see if I can find any leaks. ECM is the latest GM part (88999194?) and the prom is the base Hypertech. Any ideas? Getting even more grey hairs over this.