P0103 Running Very Rough

[tomsawyer]

Hey Everyone, I have a 05 X5 4.4i w/ 97k. Last weeks, for 3 days, the truck was running rough – uneven idle, randomly shuts off and then out of nowhere, the engine would rev between 2k & 3K. One time, I was at a red light, foot on brake, truck in drive. The engine was by itself revving and then revved to 3k which jumped the truck forward (sudden acceleration). Luckily, I slammed the brakes & avoided hitting the car in front of me. No CEL for these 3 days.
On the 4th day, CEL finally comes on. Truck is still running rough. I run up to AutoZone and the codes show P0103 & P0507. The P0103 is the MAF. And the CEL stayed on for a couple of days.
I didn’t drive the truck yesterday. Today I drive it, still running rough, still randomly shutting off, still revving up and down, no CEL.
I already purchased the MAF and I’ll install it tomorrow. Just asking, why would the CEL not originally come on when the truck was running so rough and why do you think it didn’t come on today. Also, is there anything besides the MAF that I should be worrying about or do you recommend I check or replace?
Thanks to all who answer.

[upallnight]

Before replacing parts you could have scan it with a scanner that can provide live data. You could see how many G/S the MAF is sending to the DME. This way you will know if it is the MAF.

[percodan]

I previously had an 06 750i with the same engine as yours - and had the same problem. It turned out to be a hidden crack in the intake elbow that was letting air in after the MAF and surging/stalling the engine while it tried to compensate.