PontiacBonnevilleClub.com

Hi, a newbie here, trying to make some reasonable guesses in diagnosing the cause of this MAF sensor code, and hoping for the best.

The car has been wife's DD since new, now 179,600 miles m/l. Was running fine until last week and started the missing/cutting out type symptoms. Bought MAF sensor cleaner from O'Riley's after they put their code reader on the car and gave me the printout on it. Cleaned the sensor, ran better; cleaned it again, ran even better, very little stuttering - for a while. It was running well enough to get around yesterday. Today I started out to go for an oil change and turned around for concern about getting stranded, because it had begun cutting out so badly. It has also quit a few times while idling.

Earlier this year it had a misfire code on cyl. no. 4. I ended up replacing the coil for that cyl., and all plugs and wires. It then ran better than it has been in several years, you could feel the torque again, until last week when the cutting out began. We were planning on buying my wife a new car next year when she retires, but bought one this week because of miles on the B'ville and this problem. I plan on selling the B'ville, but would like to get it running well again, if possible without spending major bucks.

One other bit of history is that we had a new cat. converter installed 3 years ago. This is one of the possible causes/fixes shown on the printout, along with wiring issues to the MAF. The exhaust does smell like a bad converter, so I am wondering if the converter may have gone bad just because parts do that, or if something else caused the converter to go bad, if in fact it is bad. A local exhaust shop will test the cat. for $25.00, though I have not done that yet. Another questionable factor is that the muffler is somewhat bad, it has been rattling at idle, like a loose baffle, for about a year, but does not sound bad as far as exhaust sound. I have looked at what info is available on the net, including a flow chart a guy has posted on this site. I don't have a high-impedance ohm meter, and am not very knowledgeable about doing that type of testing either, though I have read some about it in a book on Ford EFI.

Just wondering if anyone has any other suggestions for an electronically challenged owner, short of paying a shop diagnostic fee, and still possibly playing the replace-a-part guessing game? Thanks.

Start by unplugging the MAF to see if the car runs better. If it does, replace the MAF. Best bet for a less expensive option is one from a junk yard.

Thanks, I had read about doing that, then forgot about it. Will try it this evening.

In buying one from the bone yard, if it appears needed and I can find one, is there a calibration number involved in the meters/sensors, or any difference in years, such as 97 thru '99?

Thanks again.

Get one that says AFH50M-05 on the top, it will be from a 99-05 3800 engine.

Or you can get one from me.

I did unplug the MAF and just started it, gave it a little throttle in Park, but didn't drive it. It had an initial hesitation, like a dead spot in a carburetor, both ways (plugged in and not plugged in). I may try it again to make sure.
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I did this Friday, July 19th, but couldn't get this site to come back up to post again, Friday or Saturday, even with clicking on the e-mail link. I attribute this to our dsl provider and telephone company, Windstream. Their service is not at all up to what their marketing claims.
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Anyway, what is your price on one of the MAF units, and is it for the sensor only, or the entire MAF unit? I don't really want to change out the entire unit, and don't see any reason to do so, if it is just the sensor that is the problem.
BTW, is the throttle body incorporated with the MAF unit on these engines, or does it just appear that way to me? I am accustomed to the Fox body Ford 5.0's with the separate MAF and TB's.

Thanks again, Joe

As Archon suggested, I finally drove the car today with and w/o the sensor plugged in. Plugged in, there was stumbling and even a stall at idle, as well as some "cutting out" in accelerating and cruise. Unplugged, other than the initial hesitation or dead spot on opening the throttle, the thing ran without hiccups and pulled strong. Cleaned the sensor again (3rd time) with MAF cleaner, no help. Will get a used sensor/meter. Hopefully cased closed.

Thanks to all of you for the tips.

Got a MAF sensor from Andrew (above) about 10 days ago. After installing it the car ran fine until I pulled out of the drive. I talked with Andrew about it, and he allowed the sensor he sent could have gone bad during shipping and offered to send another one if I returned the first one. I finally went for a new cat. converter, as it was one of the reported fixes on the list from O'Reillys. The converter on the car was only about 3 years old, but parts do go bad at any time. The guy at the exhaust shop has evidently done quite a few of these things. He said a stopped up, non-functioning converter can really affect a MAF sensor. The converter tested bad, which is simply a flow, or pressure test, through the converter. After the converter was put on the car ran fine, and the CEL cleared. I thought maybe the sensor was not the problem and reinstalled the original. Ran bad again, wouldn't even idle well. Put the one from Andrew back on, ran great again and hasn't skipped a beat. So there were two bad parts, only one code. It seems though, that the bad converter probably contributed to, or caused, the demise of the MAF sensor.
Problem solved. Hope this is OK to say, I want to thank Andrew for the very quick delivery, and for being so helpful on the phone.

That is very interesting to me. I'm glad you got it fixed. I would have never guessed a bad cat would have anything to do with a MAF going bad.

I wouldn't have either Andrew. But after seeing the cat. as one of the reported fixes on the parts store printout, I thought that gave legitimacy to what the exhaust shop owner was telling me. Turned out to be correct. The car is running great and I have ads in the paper for it.

Thanks again!

The cat went bad in my wife's former `01 GP too. Caused all sorts of stumbling on acceleration issues, backfires, and the like. It didn't take out the MAF, but I'd had never guessed it was the cat. My Pontiac dealer told me there was a rash of bad ones. They replaced it free, as they're warranted for something like 10 years, and this was several years ago.