Ghost Code 44

[Truckbuck]

So I have this code for a lean exhaust that comes on after I drive on the highway for more then 45 mineuts, and once its on it turns off in a few minuets and then comes back on a few minnets later and continues to do this for the rest of the drive no mater how I am driving, even if I am parked it will turn on and off randomly.
Also when the light is on, the drivablitly does not change at all then it was before the light.
I have checked the fuel pump, O2 sensor and looked for vacume leaks with no luck. any ideas?
Its for a 93 chevy C1500 V6 4.3L and it has about 150,000 miles on it.
Thanks for any help!

[autojoe]

44 is set when 02 indicates lean condition.connect a digital voltmeter to purple wire while connected with a probe that pierces the insulation ex.bed of nails to get voltage unless you have a scan tool. start and run engine 1200 rpm for several minutes and observe voltmeter.if the voltmeter reads 0 volts or very close to zero look for a short to ground in the purple 02 signal wire to ecm.if the purple wire is not grounded replace the ecm.if the voltage is not at zero but remains consistently below 0.35 volts,inspect the following......maf sensor and false air,restricted injectors,contaminated fuel,low fuel pressure,vacuum leaks,exhaust leaks and problems in the air pump system.if all these check out replace 02 sensor.how does the engine run.....rough idle....miss....hesitation....do you have a scan tool?

[Truckbuck]

Originally Posted by autojoe

44 is set when 02 indicates lean condition.connect a digital voltmeter to purple wire while connected with a probe that pierces the insulation ex.bed of nails to get voltage unless you have a scan tool. start and run engine 1200 rpm for several minutes and observe voltmeter.if the voltmeter reads 0 volts or very close to zero look for a short to ground in the purple 02 signal wire to ecm.if the purple wire is not grounded replace the ecm.if the voltage is not at zero but remains consistently below 0.35 volts,inspect the following......maf sensor and false air,restricted injectors,contaminated fuel,low fuel pressure,vacuum leaks,exhaust leaks and problems in the air pump system.if all these check out replace 02 sensor.how does the engine run.....rough idle....miss....hesitation....do you have a scan tool?

The truck runs fine, I have been driving it for almost 4 years and it drives the same as when I bought it but the code has only been coming up the last year. Since I replaced the fuel pump a year ago. but I even replaced that fuel pump last week with a better AC Delco one and the code still comes on.
I have done a bench test on the O2 sensor and it appears to be fine, it is also less then 2 years old.
When you say "scan tool" do you mean a code reader for OBD or something else?
Thanks alot for the help!

[autojoe]

a scan tool is more complex than a code reader and can look at data stream by viewing all sensors as the computer is seeing them.you can not bench test a 02 accurately.....I know before people were using a propane torch and monitoring 02 voltage with and without propane flame.You need to tap into the 02 circuit like I described to see what is going on in the 02 circuit......would have to do this while the fault is happening while the light is on......may be an intermittent problem.the computer has the capability to correct for a lean or rich condition to a certain point to maintain fuel control.no driveability problems.......light since new fuel pump but no light or code before new fuel pump replaced?why did you change fuel pump?

[j cAT]

put a vacuum guage on it and find where the leak is.

[Truckbuck]

Originally Posted by autojoe

a scan tool is more complex than a code reader and can look at data stream by viewing all sensors as the computer is seeing them.you can not bench test a 02 accurately.....I know before people were using a propane torch and monitoring 02 voltage with and without propane flame.You need to tap into the 02 circuit like I described to see what is going on in the 02 circuit......would have to do this while the fault is happening while the light is on......may be an intermittent problem.the computer has the capability to correct for a lean or rich condition to a certain point to maintain fuel control.no driveability problems.......light since new fuel pump but no light or code before new fuel pump replaced?why did you change fuel pump?

Well for the first fuel pump, it broke, and this second one i replaced because it was an Airtex or something like that and i have heard bad reveiws about it everywere and it was still under warrenty so i just returned it and used that credit to buy the AC delco one.
Oh, okay so you mean that kind of scaner, no i dont have one. maybe i can find a way to get my hands on one.

[autojoe]

you just need a dc voltmeter and a piercing probe to get a voltage reading on the 02 circuit.if stuck lean and take propane and run along all gaskets and see if 02 voltage goes rich.....then you found vacuum leak.if stays near or at zero volts and not short to ground then bad computer if stays below 0.35 volts check above for vacuum leak......I used to use propane while monitoring the 02 voltage.....now I own a smoke machine.

[Schurkey]

I fought that crap for years.

http://www.automotiveforums.com/vbul...hlight=code+44

In the end, after dicking with it all that time...all it needed was a fresh O2 sensor. It tested good--but wasn't.