My 91 c4 throws a code 44 which we all know is an "o2 sensor -lean condition" code. The O2 sensor is on the left side pre-cat. I have checked the fuel pressure and it is a steady 35psi running or not even with RPMs up. I have read that this in law and read that this is normal for a 91.
1. The light comes of and on usually on highway.
2. All injectors have ohmed out fine and are clicking evenly when light is on.
3. Fuel economy at best is 22mpg highway, average is 16 city /highway.
4. I was getting 25+ on my way home the other day then it suddenly dropped to 23 (AC off) and light came on, code 44 again.
5. It gets better mpg at 70mph then at 60, weird huh?
6. it is an auto, no mods. Just clean air filter.
7. fuel pressure reg has no fuel smell on hose, and I would think it would be running rich if not working right?
8. I do have what sounds like an exhaust leak, not vacuum on the right side but for the life of me I cannot find it.
9. According to the gauge the car runs on the cool side, water temp unless the ac is on.
10. Should the power brake booster hold a steady vacuum if I pull one or is it bad? I feel like the brakes are not that great and that could be a vac leak?
Ask me any questions to bet her figured out, I a getting frustrated.
Thanx

Lee gnccquadracer@hotmail.com

 

I've got the same fuel problem except I'm gettin 12mpg. I'm taggin along

 

Turned out to be an O2 sensor, still working on the other stuff. The old sensor looked perfect and new too.

 

I just had the code 44 on my 1985. My analysis was:
1) Key on and pressure jumped to 40 psi and then dropped to 0.
2) Driving the car with fuel pressure gauge attached and taped to windshield indicated that pressure would sometimes drop into the 20's.
3) Tested by pinching hoses at tank.
a) Return hose from FPR pinched and still dropped to 0
b) Feel hose pinched and pressure held.
4) pulled the fuel pump - new (within 6 months) Walbro pump.
5) Looked like the pump was not fully engaged in the pulsar. Pulled out this unit and installed a short hose with clamps between the pump and hard line.
6) Tested pressure...seemed to be okay.
7) drove the car and code 44 again.
8) replaced the Walbro pump with old NAPA pump.
9) replaced the O2 sensor at the same time.

No problems currently.

 

My pressure was good and even held when I shut it off. Def a pressure issue, the connector to the o2 pigtail seems to be a common issue too

 

Generally, if an O2 looks new and it isn't, it's because it's been getting a nice steam bath. The coolant leans out the mix and sets the 44. Given the year, I'd pull the #7 plug since that where most of aluminum headed L98's have problems. If it's clean too, your head gasket is weeping and it needs more than a new O2.