The factory service manual gives unit measurements for O2s in millivolts, 0-1000 and constantly varying for both 1&2.

 

Ok i meant to say 600-700 volts.

 

Millivolts!, but I know what you meant. I might hook up my tech II today to see how that compares. Did you use the Cataclean yet? What are the results?

 

yes I mean millivolts,i found that when I pinched off the main vacuum line going out to the sensors that my STFT went down to 3% it was at 12% .some where along that line is vacuum leak...have not put cat clean in yet,code went on this morn,waiting to be a 1/4 tank,im close now little below 1/2..

 

Hooked up the Tech 2. Here's what I came up with. From eng. temp. cold at start up both STFT & LTFT were at 0% +/- 1-2% at idle (725 rpm). I ran through some other diagnostics like HO2S sensors 1&2 and found them as described, varying in range from 0-1000 mV but more or less stable around 600-700 mV when I accelerated to 2500 rpm. Rechecked The FTs after 20-30 minutes idling and LTFT went up to +16% which I believe is normal due to the long idle time. Then monitored while driving up to 40mph and both STFT & LTFTs went back to around 0%. So in conclusion, you may have seen the 16% after a long idle time like me and you don't have a vac leak at all. The HO2S sensors are normal, so the problem is the Cat. To confirm you should go for a drive to see if the 16% LTFT drops like mine.

 

BTY- I bought the car new in 2001. At 100,000 miles a did a major tune-up using all OEM parts except and UIM the LIM gasket which I used after market improved versions of. Replaced all plugs, plug wires, coil packs, ICM, PCV, TPS, IAC motor, all 6 injectors, air filter, LIM gasket, UIM, and cleaned the MAF. It now has 125,000 and think it's running pretty much perfect.

 

there is a hose that splits off one side goes to map sensor and the other side goes through the fuel rail sensor..when I pinch it off I get 0% STFT ,it was 10% ..after that line I pinch doesn't do anything,could fuel injectors leak vacuum?
line.jpg

 

The injectors themselves are under fuel pressure and electrically activated. There could be a leak around an o-ring where it is sealed to the intake manifold, but I would think you would see and smell a fuel leak.

 

put the car clean in and drove 45 miles..will check sensors later..what else could that vacuum leak be?

 

Did you check the tubes around the EGR? It's hard to find the cracks.