Help diagnose RPM drop when accelerating

So today I was on an hour highway drive back from some Xmas shopping when I noticed that while in 5th gear if I tried to accelerate quickly, the RPM's woud start to rise, but then fall maybe 1K lower before starting to build back up again. This happened in every gear and was most noticeable if I just all of a sudden floored the gas. It's never done this before and I haven't noticed the clutch slipping when shifting until not either. Any ideas on what the problem could be, or if it is indeed a worn or glazed clutch? Any ways to test without taking it in?

Originally Posted by Jrob1

So today I was on an hour highway drive back from some Xmas shopping when I noticed that while in 5th gear if I tried to accelerate quickly, the RPM's woud start to rise, but then fall maybe 1K lower before starting to build back up again. This happened in every gear and was most noticeable if I just all of a sudden floored the gas. It's never done this before and I haven't noticed the clutch slipping when shifting until not either. Any ideas on what the problem could be, or if it is indeed a worn or glazed clutch? Any ways to test without taking it in?

Interesting...I haven't had that happen exactly, but I had a hesitation in each gear. The car would accelerate, then pause, accelerate, then pause. It ended up being bad O2 sensors even before the car threw any codes. If you have over 90-100k miles with original O2 sensors, keep this in mind. Then again, if RPMs are actually dropping and it seems drivetrain related, this would not apply. Good Luck either way.

Anyone have any input on this at all?

How many miles does the clutch have on it? Clutch slippage starts in the lower gears(6,5,4) then moves to the higher gears(1,2,3) as things get worse. A good way to tell if your clutch is about to go is to perform a couple of launches and see if the clutch still holds.

I'm at about 74K right now with the stock clutch on there. I just think it is strange that it started happening so suddenly and I definitely don't abuse it at all. Well I guess if I have to replace it then I might as well go UUC. Annyone using the moderate weight steel flywheel with the performance organic clutch? I thought this might be a better option to reduce the possibility of chatter.

Bump

I have a ZHP "M54 Motor" I got 65k on the meter and in second gear at 2900 RPM I get a sudden power Loss/Dip.I have SS Headers/Race Cats/Muffler but no Engine software.I think my problem my be the Air/Fuel Ratio is off due to the aftermarket Exhaust System or a New Vanos Seal Possibly.I will be taking my car to ESS for the Software/Vanos Seals shortly so if that seems to clear the power dip ill PM GL on Diagnose

My problem is really only under hard acceleration when the tach is above 2500 or so, then it just seems like something is slipping and the RPM's shoot up then drop down before the car starts to accelerate.

Originally Posted by Jrob1

My problem is really only under hard acceleration when the tach is above 2500 or so, then it just seems like something is slipping and the RPM's shoot up then drop down before the car starts to accelerate.

+1 worst in 3rd & 5th gears, but noticeable in all.

Bump for any other opinions.

I just started to have this same problem in my 2003 M3 vert. I only have 62k miles on it and it just started this last week. Was this issue ever resolved or did anyone come up with an explanation? Mine is also only in gears 4,5 and 6. Noticed on the highway as well when I floored it, slight pickup, dropped 500-1k rpm, then slowly picked back up. Please help before I have to take it in!

Hey there,

I noticed a similar behavior to this but only in 1st with the AC running stopped to go up a hill. I actually stalled my car trying to start climbing. What happened was I was quite easy on the throttle and the rpm's dipped and that stalled the car. I could over rev and then "launch" up the hill. What I did was reset the adaptive throttle. It was easy and free. The steps are simple:

1. Turn ignition to position 2
2. Count 10 seconds
3. Turn ignition off
4. Count 10 seconds
5. Start the car

Before sinking all this money into what sound like young clutches (mine is at 68k miles and I have a buddy who is at 98k) -- give this a shot. Also, check into vacuum leaks as they cause rpm dips as well.

HTH

sorry if im bringing this back from the dead but i need a diagnose of this problem also any help would be nice

Pressure plate needs to be replaced. Sometimes it can go before the clutch disk itself. My car had this issue. It would slip some days and others it would grip just fine.

Originally Posted by ///M=Power

Pressure plate needs to be replaced. Sometimes it can go before the clutch disk itself. My car had this issue. It would slip some days and others it would grip just fine.

ic mines slip everytime when i floor the gas pedal, rpm jumps up then goes down then i can feel the car moving lol i mined as well upgrade the clutch, pressure plate and flywheel if thats the case

Originally Posted by Cdizz

ic mines slip everytime when i floor the gas pedal, rpm jumps up then goes down then i can feel the car moving lol i mined as well upgrade the clutch, pressure plate and flywheel if thats the case

just replace the clutch with an oem clutch kit from turnermotorsport they are like $250... you dont need to replace the flywheels in our cars contrary to popular belief that you have to replace the dual mass flywheel every time you change the clutch. a lightweight flywheel is more of a pain in the ass rather than good, yes it makes your car feel a little quicker, but it chatters and shifting is rough along with takeoffs and traffic sucks with one. stock clutch is more than fine unless you are seriously tracking your car.