MAF sensor on a 2001 Impala 3.8l

[Im Lon 2]

Originally Posted by mattridessleds

After replacing this sensor twice with no luck I am wondering if the sensors are manufactured for specific vin#'s. I've tried the re-manufactured ones and also one off a junker.

Try replacing the PCV, and MAKE SURE you replace the O-ring on it too.. That fixed all my problems.. Wasn't the MAF after all.

[SpinnerCee]

Does the O-ring typically get wasted when you try to replace the PCV? do you typically get new O-rings with a new PCV?

I know a lot of parts on the Imp are meant to be replaced when they are serviced... are the o-rings one of them?

* I hate the torque-to-yield bolts (ie: head bolts) that once they are torqued once (read that, stretched) they are history.

[Im Lon 2]

Originally Posted by SpinnerCee

Does the O-ring typically get wasted when you try to replace the PCV? do you typically get new O-rings with a new PCV

No the O-ring did not come with it. Nor did I see it when I took the old PCV off. But it really makes the car run like crap with out it.

[SpinnerCee]

That makes this a good tip

[richtazz]

There are 2 o-rings in the PCV housing on the 3.8. The big orange one at the top of the housing, and a smaller black one that goes on the PCV valve itself. The black one is the one most people miss and causes the whistling/squealing noise and odd codes to pop up. The most common code caused by this missing o-ring is a p0401 (EGR insufficient flow detected), as the PCM uses the MAP sensor vacuum signal to determine EGR efficiency. Since the MAP is mounted in the top of the PCV housing, a vacuum leak will cause a low vacuum reading, tripping the P0401 code. Other air flow related codes can pop up also due to the vacuum leak, so theoretically this could be the cause of your MAF code. Normally a p0102 (mass airflow low input circuit) is caused by a bad MAF or the wiring between it and the PCM, but it's not impossible that it could be caused by a vacuum leak.

[jleer]

2002 impala 3.8l 9c1, my car had a rough idle, and would die after warm up, things that were changed were all 3 coils, spark plugs and wires, map sensor, idle air control valve, cat convertor, fuel pump, fuel filter, throttle body was cleaned, maf sensor was cleaned. all these parts and no effect on the running of the car. took it to a trusted mechanic, and he did multiple test on all the sensors, and had good readings. he checked the fuel pressure regulator on the fuel rail it was ok. he did a pressure test on the fuel supply it was ok, he removed the fuel line from the back fuel rail and shot 200 psi air through it make sure there wasn't a restriction ,with the fuel cap removed of course. hooked everything back up, still there was no difference in idle or running, we did a road test, and car ran horrible with hesitation and misfire , pulled over disconnected the maf sensor got back in and took off, and the car ran like it was brand new, plugged back in the maf, and all the symptoms were back, we put in a new maf sensor and the car runs great. I've spent over $1500 in new parts before the maf sensor/ it seems just cleaning my maf sensor didn't help it at all, so if you have problems like mine, unplug the maf take it for a short road test, if it runs great than get a new one, hope this helps some else with the same problems before they spend that kind of money

[iamiancamp]

To jleer.
I had the same problem as you and unpluged the maf sensor and it runs great. Bought a new one and im happy again. Very helpful story thanks.
Also my car is a 2002 impala 3.8, 9c1 police package.

[Mojorisin]

Originally Posted by Im Lon 2

Well, just like others I have read.. Works great for a couple of days and then right back at it. I don't get it. I just got some MAF cleaner and seems to be running good again. But I don't feel comfortable about it at all.

Just curious could a plug be fouled and just throwing the car off? I bought new plugs, and wires but have not had a chance to change them out.

I'm getting really close to take it to the dealer, but god knows they are going to change everything like I'm doing now till they find a problem.

Once again I have no clue

I have replaced brand new mass airflow sensor, and seemed to solve problem for a couple months.... then 2002 Impala would hesitate in starting, idle uneasy when giving gas and at its worst - Driving at highway speed stall or stutter out. I cannot give it gas, and only option is to have it die out, no air, no gas, then no power. Start it again until it happens again. Mass Air flow is not the solution, but works well when you replace with new one. I went through two new ones, and now its starting again!!!

[maxwedge]

If these are reman units from Cardone they are unreliable from my experience.

[Tech II]

There are "new" ones and there are "new" ones....

Had one 3.8 where reman one failed right out of the box.....got another, it lasted one day and failed(easy to check with a scan tool by looking at MAF data)......customer wanted the el cheapos, until he got stuck a second time....bought the more expensive GM reman, and had no problem after that....a brand new GM one is out of sight....

[la1]

I would like to add that a lot of 3.8L Impala issues can also be with the intake manifold. They are plastic and can warp, especially at the throttle body and also the mating surface. There is also an issue with I believe where the EGR comes up through the manifold. This is just info I have heard, I have a 3.4L that has the metal intake manifold, even with that I recently replaced the upper intake manifold gaskets and it made a considerable difference in the running of the car.

[lionstone22]

Although this thread is pretty old, it appears to have some really good information regarding the same issue that i was experiencing.

Symptoms
Hesitation/stubbling at low RPMs
Periodic surging/bucking at all speeds
Stalling at low speeds/idling
Symptoms would disappear for several days and then reappear at different times.
Initially, no check engine code

None of my symptoms prevented me from safely driving, but they were annoying and sporadic.

finally, after a couple months the check engine light came on. It was a P0102.
This finally gave me some direction and i ended up in this forum. I removed and cleaned the MAF with CRC MAF cleaner and cleared the codes. So far my car is running better than when i purchased it in January.

If any symptoms reappear after time, i will also remove and clean the throttle body. I tried to clean it without full removal, but did not do a very good job. It is pretty dirty.

I would like to note for the less informed, that the MAF is very easy to remove and clean, but mine (and i assume most) have security screws holding it in. I had star bits, but no security star bits. I went to Harbor freight and bought a security bit set for $10. After that, it too less than 5 minutes to removed, clean and replace.