About a month ago i got a code 44 so i replaced the o2 sensor, then ses light didnt come back on. then 2 weeks later my cat converter stopped up and in the process of me "trying" to get it off i rattled the o2 sensor to death and had to replace it. So that was about 2 weeks ago. I didnt have any problems until 3 days ago, car started running like crap, just like the o2 sensor was bad. I pulled two codes; 34 and 44. Im confused because i just changed the o2 sensor 2 weeks ago and i bought a brand new MAF last summer. WHAT COULD IT BE??????? And even though the code says im running lean im really running rich (bad o2 sensor).

 

Your symptoms and codes are screaming to me "Vacuum leak!"

Having the oxygen sensor report a lean condition, while the noted operating conditions are actually rich, indicates an air leak to the exhaust manifolds, or a degraded condition of the O² signal from poor grounding or wiring. The leakage could be from damage to the manifolds or 'Y' pipe, or could be from an air injection system that has a stuck or leaking port/divert valve or air tubes.

The '34' indicates a lower than expected MAF flow under given engine RPM and throttle position conditions. If the TPS voltage is correct, the engine may be drawing air from a source that isn't routed through the MAF. These potential leaks include any vacuum hose, intake gaskets, the PCV system, using a breather-type oil filler cap instead of the required sealed cap, a power brake booster leaking internally, or damaged intake ductwork downstream of the MAF sensor.

 

Couple things I remember...as once being a member of the "Code 44 Club"...MikeinAZ was the president, BTW...
But I had a similar situation, that caused my O2 voltage to dive to 15-20mv's, although the car stunk like raw fuel...after going through all the code 44 diags, my MAF was bad, saturating the O2 sensor with fuel, not allowing it to read any oxygen content.

In fact, part of Code 44 diag says to disconect the MAF, and see if code 44 goes away, if so, replace MAF.

Dunno if it helps ya, but worth a shot.

 

"Code 44 Club" - Wow - That was a long time ago.

Have you checked the mV output of the MAF at normal idle? That might prove the MAF good or bad.

 

By the way, i have a custom ram air that goes from grill through 2 inch tubes to my air boxes that have the origional bottom cut off. I forgot to note also that before i was even getting the ses light the car would sometimes start to die if i was just coasting slow without touching break or gas. And also when i had to come to a quick stop. The SES also SOMETIMES comes on if ive been sitting for a while idling, but once i get moving again it goes off about 2 minutes later. AND it SOMETIMES comes on when im driving at higher speeds and i noticed 3 times that it would go off when i slowed down to turn.

How do you check the mV output of the MAF at normal idle? And i disconected the MAF and ran the car to look for a difference it still didnt run that great but the ses light came on almost right away after starting it, unlike with it plugged it takes a long while to come on.

Well i was talking to a guy about the possibility that it might be a vacuum leak. He told me to buy carb cleeaner and spray it little by little through out the engine compartment. If i spray near the leak in a hose or what not it will be sucked in and the idle will rise. Is this true? Is it safe? im not gonna saturate it in cleaner but just coat it a little.



Seems like this type of stuff happens once you are trying to sell a car, doesnt it.

 

I struggled with this for weeks on my pontiac 6000. I would come to a stop at a light and the car would start to stumble and act like it was going to die. The check engine light would come on and set a map sensor code and o2 sensor code and it had rich exhaust fumes when it was acting up It turned out it was the egr valve hanging open at idle, check the egr diaphragm to see if it moves freely, you should be able to push the diaphragm up without too much effort. If not lube it or replace it.

 

Testing MAF output? You'll need a digital voltmeter and tachometer.

Backprobe the 'B' and 'C' terminals on the MAF electrical connector. The MAF will remain connected for the test. Start the engine and allow it to reach normal operating temperature so the idle RPM is normal. Read the voltage signal from the MAF at the digital meter.