Hi..I recently got an engine light and did the paperclip thing and came up with a "44" lean code. My O2 sensor and fuel filter are only 5 months old(along with a complete tune up) and I checked the O2 sensor wire and its not burnt or broken.

So I figured maybe its a fuel pressure issue since my car seems to surge a little at higher rpm's. I hooked up a gauge and came up with these numbers:

With the vaccum line to the AFPR connected:
44psi...with just the pump running...39-40 at idle

With the vaccum line off:
46...with just the pump running...49 at idle

Which reading is more accurate? It seems like the pressure is there. Could it be an injector issue?

I'm a little clueless in this department.

thanks

 

It would be a fuel pressure issue only if you had a low fuel pressure reading. Code 44 = Oxygen Sensor Circuit (lean exhaust indicated) This could be caused by a exhaust leak, contaminated fuel, vacuum leak, O2 sensor wire too close to exhaust manifold, Maf Sensor, or an intermittent ground in the wire between the O2 sensor and its connector.

 

Man, OBD1 is so non-specific! I'm pretty sure my gas is OK, I checked the O2 wire and it seems to be out of harms way, I dont have a MAF(I have speed density), I have a small exhaust leak at the header flange(but I've had that for 2 years now), so I guess that just leaves a vaccum leak or the map sensor.

But wouldnt the map sensor failure code come up also if it was related to that? And my car doesnt seem to run like it has a vacuum leak. Damn, I wish it was an easier fix.

And you figure if it was a wiring problem to the O2, it would have come up when I had my A/F ratio gauge spliced into the sensor wire...but it didnt. I've had that disconnected for 2 years now!

I guess I have to take it to a shop. Can I be harming anything driving around with this code coming up?

 

Sorry about the MAF spelling, meant to type MAP. A MAP sensor output that causes the ECM to sense a higher than normal vacuum will cause the system to go lean. You can test this by disconnecting the MAP sensor, if the lean condition is gone replace the sensor. If your exhaust leak is above the O2 sensor, the outside air being pulled in can cause a lean condition. The same thing with vacuum or crankcase leaks.