Hey guys,
So I had a dead cylinder but car ran and idled just with a miss. I found a bad spark plug and replaced it. Now I get error code 44 - Oxygen sensor lean. If I am in gear, it won't idle, it dies. When in park or neutral, the idle constantly fluctuates between 500 and around 8-900 rpms. I step on gas and it'll smooth out but as it gets down to 1000 rpm, it drops to around 500 and starts the cycling again of moving from 500 to 900 rpms and back. Any thoughts/ideas? I have replaced the oxygen sensor, fuel pump, and fuel filter.
Thanks.

 

What's your fuel pressure? Check for vacuum leaks, the line to the regulator especially. What do your plugs look like, dirty, gassy, bright white?

 

I don't have gauge to measure fuel pressure. I didn't pull any other plugs to check them. Where is the regulator located?
If I get gauge to measure fuel pressure, what should it read? Is it a range or should it be a set number?

 

Is this a tpi or carb car? I made the assumption it is tpi but I don't want to be incorrect at it changes everything

 

It is a TPI.

 

passenger side of the engine you'll see this. Key on, engine off should read around 43 psi. Running and vacuum line hooked up usually ends up at about 38 psi.