Ok so here's the deal, this is my daily driver. I drive this truck about.. 350 miles a week, and it's got 100946 miles on it, only been modded the last 20k tho.

First mod = K&N CAI

Throws a PO101 code, which is Mass Air Flow (MAF) Circuit Range/Performance.

Clear it, it never comes back.. alright

Finally get a Cam and such in it 7 months later.. Throws the code again.. I'm having MAF problems. Tuner says that the MAF is functional and he can't figure out why it throws the code when the MAF is working just fine.

So about every... 3 weeks I throw a PO101 Code, but it never limits the truck at all, never stalls or anything.. Truck Runs great..

2 weeks ago the truck starts to spit and spudder at lower RPMS, and every day it's gotten worse since then.

The problem has gotten to where the truck is running rich enough to black smoke, leave black spots on the pavement when you rev it, and it runs like absolute ***. I cleaned the MAF as well as the pigtails and such because when we hooked the SNAP-ON computer up to it, it said my MAF was showing 0 volts.. also the bolo or w/e was at 29.9. But it also said to have a air/fuel mix at 14.8.. and it just earlier threw a code for running too lean on (bank1).

Has anyone experienced this problem or have a solution?
How many pins in the MAF pigtail should be hot while the vehicle is running?

 

If the MAF is showing 0 volts, thats your problem. A lot of tuners will turn off any MAF codes because theyre too lazy (or dont know how) to tune the VE table and its a sanity check for the MAF.

The running too lean is from the O2s. Replace the MAF with a know good one.

 

Do you know how many pins in the pigtail running to the MAF should be hot while the truck is running? i only found 1 but i'm not sure about the others :S

 

I'd guess 2 are hot. 2 go to the IAT sensor and 2 go to the MAF.
Also if you have an OIL type filter, over oiling can cause oil to get on the maf sensor and make it malfunction. Cleaning the sensor usually fixes the problem and going to a dry filter or carefully oiling next time.

 

any idea which 2? With my clip on top, from left to right, the 2nd one is the only one i can get a test light to light up on..

 

Not sure which wires are which without a schematic, but you don't want to test a MAF or it's wiring with a test light, it does not have enough resistance across the bulb and could fry the PCM. Get a digital multi-meter with 10 megaohm impedance to play it safe...a decent DMM is less than $40 from Sears, Radio Shack, etc.

 

If your MAF was going to 0 volts, that makes me think that one of two things is happening.

1) intermittent open circuit in the harness.
2) MAF sensor is no good.

Easy thing to try is borrowing a known good MAF sensor for a while to see if the problem goes away. Take it from there.

 

Ok so after all this trouble, i tested the pigtail with an ohm meter, compared it with a perfectly functional pigtail on a truck same year model and everything tested fine. I own a parts store here so i took a MAF off the shelf and tried it, didn't change anything. I took it down the road, gave it a couple of good runs, throws the same 2 codes, lean on bank 1 and MAF performance. Put my old MAF back on, figured there is nothing else it could be other than an O2 sensor, which i had a spare. Swapped the O2 on the drivers side, purrs like a kitten..

It still throws the MAF code, like it's always done, but it runs great and isn't running too lean or rich.. Idk what to do about the MAF because even a new one acts the same way.. but as for my main problem, it was a simple O2 sensor.. thanks for the help though guys..