Ok, i had my laptop hoooked up to my obd 2 port while driving to read all the 02 sensor voltages, after driving for an hour while reading the voltages, i realized a few things #1 the 02 sensor only puts out voltage when im below about 15% throttle, anything above that the voltage shoots right down to 0 (The other 02 sensors are all still showing voltage) and if im sitting in neutral idling the 02 sensor outputs voltage (they all do). and if the engine is under a load (driving up a hill) the 02 sensor outputs very little (.030 and less) to no voltage. remeber im talking about the pre cat 02 sensor. The 02 sensor right after the cat (test pipe) about2 feet further down the exhuast system puts outvoltage like its supposed to and the02sensors in each manifold put out voltage like there supposed to(fluctauting between .1 and .9 volts). What does this sound like, a defective 02 sensor?

 

Well, thanks for all your help guys, turned out to be a defective 02 sensor, replaced it, now im getting voltage at all rpms and loads from all the 02 sensors. One more question though. After monitoring the 02 sensors, i realized theres something wierd going on with the fuel trim adjustment and just wanted to see if you guys think its normal or not, what happens is about 1/2 time the fuel trim adjustment alternates from working on the bank 1 sensor 1 and bank 2 sensor one (the ones on the manifolds) to not working and then working on the bank 1 sensor 2 (pre cat) sensor, its always either the 2 on the manifolds or the 1 on the pre cat adjusting the fuel trim but never both at once (im also getting codes P170 and P173 fuel trim malfunctrionsnow, dont know if that has anything to do with it), here are some pics so you see what i mean.
http://s145.photobucket.com/albums/r...=Voltages1.jpg
http://s145.photobucket.com/albums/r...=Voltages2.jpg[/align]

 

Do not think I would find that to be abnormal War97GTS. The engine is going to be looking at each bank for more fine tuned mixture adjustment from side to side of engine when monitoring the upstream sensors and would be doing an overall engine adjustment when monitoring the pre-cat sensor. Do not think it would be watching both as when the two banks of exhaust merge you would be getting a different reading than individual banks. Have you reset the fuel trims by disconnecting battery cable after replace of the pre-cat sensor. Clear codes does not reset fuel trims and is maybe just still recovering from the faulty O2. You will want to take a look at the Long Fuel Trims numbers for bank 1 and 2 to see if the system continues to run either rich of lean. Positive trim numbers mean a lean condition and fuel amout is being added. Negative trim numbers mean a rich condition and fuel is being subtracted.

 

OK so i disconnected the battery for about 5 minutes also held in the brake pedal for like a minute to deplete any remaining charge. then codes p0170 and p0173 came back again after like100 miles. I remember i was adjusting my tps and i accidently leaned on the fuel pressure regulator control solenoid and broke off the end piece of it with the mitsubishi symbol on it along with the platic nipple that sticks off of it. i dont think it mattered becuase there was no connection to any vacuum lines on that anyway, but is it a possibility that has somethin to do with it?

 

Fuel pressure regulator is listed at the top of possible causes for both codes. Not sure which part of the solenoid was broken off. Was it the oval air filter end? If both of the other vac lines are hooked up. One to the intake manifold and other to the pressure regulator and vacuum control to the regulator is normal then the system should still be operating normally so would not think it would be. The codes do not indicate is system is too rich or too lean on these early cars so need to determine that by looking at the long fuel trim numbers. Fuel pressure regulator diaphrams have been know to rupture and draw fuel directly into the intake thru the vacuum line. Just a thought.

 

yea it was the oval end that broke off (the cap that has the mitsu symbol on it) i gotanother one at the junkyard today so ill put that in and see what happens, it cant be the fuel pressure regulator becuase i just put in a brand new oem ford one (150$) so what do those codes actually mean?