Got another odd issue. I use to have a kn cone filter on the car for 3 years until with issues with my dealer made me take it off so they would shut up. I was having a problem when in 3rd or 4th gear anything under 40% throttle the car would bog down in rpms and slowly increase but if I went over that percentage it would get going. Dealer blamed it on kn intake so I removed it and it still had the issue. They ended up replacing the torque convertor which did not solve the problem. I ended up living with it for the past 6 months. Last month I decided to replace the drop in filter with a kn version.

Now to this. About a week after changing it, at a street light my car dinged and the traction control off showed up on DIC. When light turn green it was banging into gears theng message went away and shifts were normal again. Last time I unplugged my maf to diagnose the bog problem and it did this which is from what I read gm way of saying failure. Anyway car ran fine until yesterday.
On my way to Hershey park the car banged into second gear but the other gears were fine.. Then the next light it was fine as well for the next 30 mins. Then at a light it hesitated to go from a stop and then banged into gear. No traction control message came up at all this day. . I plugged my obd reader in and I noticed my air fuel ratio would drop to 11-12 and this was when it would bang into gear but after going to jump back up to 14.70 and be fine. Sometimes during the ride it would do this while others it would stay at 14.7. Today I went to clean the maf and my screen was missing? It must of fallen out when I did the filter change bc it was on there before. I ended up picking up a whole new maf since they don't sell just the screen. It will be here Thursday. Could my maf be shot, no screen causes issue? Or could there be something else. Car is an 07 impala ss 52600 miles stock with magnaflow exhaust.

 

sorry if my message was crappy, i typed it from my phone as i wanted to submit it before I got home.

I just wanted to add that i noticed that the air to fuel measurement would only change if the AC was on. Yesterday the AC was on and it would randomly drop to 11-12 for about 3 seconds and jump back to 14.7. On my way home today, it actually went up to 16 for a few seconds and dropped back to 14.7. It did this after I turned the AC on and only seems to adjust like this when I am stopped or coming to a stop..

I am trying to get some advice b/c this only happens sometimes and my luck it goes to the dealer and the car doesnt do it.

I did buy a whole new MAF b/c i needed the screen but I am most likely going to put the new one in once it arrives. It is a ACDELCO part from GM parts direct

 

I know the screen is important. It's purpose is to straighten out the air flow. Without it you will see worse MPGs and less power. However I don't know if it's the main cause of your problems or not.

 

yes i know the screen is important, especially on an auto trans as you said helps the MAF read correctly. I am not sure how I lost it. I did a quick filter swap and was having issues trying to get the bottom part of the air intake box to snap in. It must of fell out and I never noticed. It wasnt sitting in the intake box and there no way it got sucked into the engine b/c lol i think i would notice that plus it to big. I ordered a whole new MAF for 60 bucks from GMpart direct since they dont sell the screens. I did a lot of googling and a lot of cars from all makes have 1-2 shift problems with a bad MAf or dirty one..

 

I would clean the maf first to see if helps out,I clean my twice a yr .I get the service stability traction control message every 1 or twice a yr,hopefully its not a hub going bad.

 

yea i cleaned it this morning and didnt shift hard but I am just going to install the brand new MAF once it arrives. The thing i still notice is the random drop and increase in A/F ratio only at a stop or coming to a stop. Before it would never leave 14.7. Even on hard acclerations (WOT), at stops, or normal driving. I know about the hub but if you unplug the harness from your MAF sensor and start the car, the traction control off light will come on and you get harsh shifts 1-2 and mild shifts 3-4. Plus you wont throw a code right away either with it unplugged. The fact that it showed this message and I had a harsh shift from 1-2 about 2 weeks ago makes me believe that my MAF is starting to go bad. What confused me is i didnt get that message on my way to hershey but was getting random hard shifts only 1-2 and one time i had a loss of acceleration at a stop and then bam. I no having no screen in place but a brand new oiled KN filter might of caused that as well. The screen was in before i changed the filter and I know that for sure.