Birdland

Any ideas of what is causing my truck to bog down/moan if I checked the air filter box today and the foam is still in tact? I just noticed it today in 25 degree weather. When accelerating at around 25-40 mph it feels as if the engine is groaning. When I let my foot off of the accelerator, the moan continues for another couples seconds and then returns to normal. I've searched a bunch of threads but couldn't find an answer for what else to check if the problem isn't being caused by bad foam around the air filter box.

FYI I have a 2005 Lariat with 101,000 miles. Thanks!

Especial86

iTrader: (1)

I've actually mentioned this in another thread today, but try doing a search of "CMCV plates" that are located on the intake manifold.. They are butterfly plates that regulate air flow through the intake manifold after it passes through the throttle body... A malfunctioning servo or hang up in its function can cause bogging and or a moaning/groaning sound

Birdland

Thanks! I'll look into the CMC plates. If this is the problem, is it an easy fix? Hoping it's nothing too serious because I just had to have the head pulled last month to change the spark plugs!!!

Especial86

iTrader: (1)

Yes it's easy... If you had the head pulled, then I'm willing to bet that the intake was also pulled and possibly damaged, or the CMCV plate motor on the intake was never reconnected... In light of this new evidence of the head being off, I would certainly check the intake manifold...

Birdland

Update- I replaced the foam gasket arounnd the air intake box today just to do it. The original gasket wasn't too bad off but I figured I'd go ahead and replace it anyways. I also pulled the MAF sensor and sprayed that up and cleaned it. Then I pulled the air filter box off and cleaned up the butterfly valve with some throttle body cleaner. There was a good amount of carbon build up on the valve. The moan is still there but is not as pronounced. I even can hear it right when I apply the brakes but then it goes away. Still not sure what else to check. No check engine lights are coming on, should I just let it be and ride it out? Besides this the truck seems to be running great.

I will admit the one bad thing about this forum is I keep thinking something is wrong with my truck after reading potential problems with these trucks!!!