When the DISA valve hangs up the power drops off. Remove it from the intake and inspect/clean. Search DISA valve cleaning on youtube. I would start there.

Well since I don't race the x5. Accelerating ain't a big deal it's plenty fast enough accelerating. The only code I come up with is the airbag on the passengers seat.

Not normally fast enough to take a 5.0 mustang but fells like it might when it does that rare fast accelerating. I really don't think a stock 3.0 n/a should move like that.

Well since I don't race the x5. Accelerating ain't a big deal it's plenty fast enough accelerating. The only code I come up with is the airbag on the passengers seat.

Not normally fast enough to take a 5.0 mustang but fells like it might when it does that rare fast accelerating. I really don't think a stock 3.0 n/a should move like that.

Just remove the DISA Valve and check the flap. There should be tension when you move the flap and it should snap back. If it doesn't snap back or you don't feel any tension while moving it you have a bad DISA Valve.

While the resulting symptom would be less performance all the time, the leak in the boot connected to the throttle body if after the MAF will alter the air/fuel mixture toward the leaner side.

and a hotter running engine. Not "hotter" more power, "hotter" overheat/warped head.

Its I little upsetting that you guys know more about my vehicle then I do without even being anywhere near it. This makes me sad but happy and the confusion hurts my head. So I think im just going to sneak in your homes while you sleep and secretly replace one of your frosted flakes with a plain ol corn flake. Yes im evil that way.


Jokes aside I really do appreciate all the info, tips, and help you fine gentlemen provided. Thank you, Jake

I'll jump in & listen for answers... Mine (a 3.0 with manual trans) does that on occasion as well; when accelerating from a stop, usually just before shifting to the next gear, it's like somebody stomped on the throttle and it jerks forward. It only lasts for a split second because it comes on just as you start to depress the clutch, and is done before you can do anything else to see if it keeps accelerating. It happens right around 3000 rpm, and only does it on that first shift, never on subsequent shifts.

I doubt it's a vacuum leak; just replaced the intake boot, and checked for other vacuum leaks while I was in there. Could be the DISA valve; will check that. I was also wondering about VANOS; CEL is on, but I haven't had the codes read yet.

Well gentlemen I think I have found the problem... first no slapping! Thanks to your help and a little of my own blood (stupid hood) I may have found and corrected most of the problem so far for under $10. But I still need one more part. So I finally got time to take apart and inspect. I was taking the intake out to check lower intake boot and disa valve. When I touched a vacuum line and watched it disintegrate before my eyes. Seriously it made me laugh to watch that. I found 2 small cracks in the intake boot and temporarily patched them with electric tape and duct tape (already taken off) I then began replacing vacuum lines. I get a great deal on stuff like that.
First start after still made a little noise but stopped in a few seconds. let it run about a minute.
second start. no noise idled a little lower. let it run about 2 minutes.
third start. no noise let it hit operating temp then a little revving... 1.5k slow rev(no noise) 2k slow rev(no noise) 3k slow rev (no noise) just about to do a slow 4k rev when my neighbor yells down. " So you finally figured out your vacuum leak!" I've said probably 10 words to this guy since he moved in. I shout back up "yeah I think I did". He then says "I was wondering when you were going to figure that out!" come to find out he has a mini and a 330 both not stock. I thanked him for not letting me know the problem sooner. He said he knew I would figure it out sooner or later.

I then decided to take it for a test drive. about 50 miles into the test drive. I get my first kill story!!!!! I catch up to a little green honda civic with BMW badges riced out! after laughing out loud with my widow down he heard me. We make eye contact he shouts out "BMW bitch wanna race!" NOTE I can see the "H" on his steering wheel. I really don't think he saw the grill or logos or for that matter even really knew what a BMW x5 looks like (but he does now) He revved that big ol fart can exhaust the light turned green I took off I hear the bumble bee getting quieter with a couple times it sounded like he was going to catch up (vtech kicked in) then he'd shift and I pulled away my X was in rare form. and now because of that little bit of fun.....I WANT AN X5M!!!! or any turbo model. yes it's on my Christmas list...and Birthday list as well as any list I get something free.

Thanks again guys

Never fear a 5.0 mustang. Remember that you have all wheel drive, gear ratios, redline, and Vanos on your side. (Not to mention really wicked negative rear wheel camber for any turns that come up)

2002 X5 3.0 243,000 miles
2004 325i 108,000 miles

1970 Trans Am under restoration (that you can fear);)