acceleration issue

[oystershot]

I am having a puzzeling problem. I have a 325I that has about 67,000 mi.
I have started to notice an acceleration problem when I am on the freeway.
When I get up to about 65 mph and slowly try to accelertate, the motor
seems to oscillate. It speeds up then slows, then seeds up , then slows
until i give it more firm throttle pressure. At about 68 to 70 mph the car takes
off. I just put in new Denso plugs, a Turner chip, and cold air system. The car was having this problem before the mods so I know it isn't that.
Any input would be greatly appreciated.
Thanks guys.

 

[epj3]

Sounds like a fuel pressure problem... but I am not positive. I hope someone helps ya out!!

 

[bmwboy]

is your car auot or manule cause if its auto it could be related to the transmission. not sure thoguh and good luck

 

[oystershot]

It definitely feels like a fuel problem. Would the fuel filter do this?

 

[epj3]

It definitely feels like a fuel problem. Would the fuel filter do this?

Well, if it were the fuel filter, he would get the same problem at lower speeds... though only getting it at higher speeds doesnt make much sense either...

So now I'm thinking it might be transmission software?

 

[f1racer77]

I'll take a wild guess here and say maybe dirty injectors, but only if it acts the same way at 30mph also. If not and its an auto. transmission software.

 

[oystershot]

Thanks for all the great input. I was not aware there was software for the auto trans.
If it were the software, would it only occur in that small acceleration range (65-70 mph)?
If in fact it is a software issue, how do I fix it?
Thanks again for the time and patience.

 

[oystershot]

By the way. I forgot to mention in my orriginal posting that this was a 1994 325I.
I don't know if that makes a difference with respect to the software issue.
Thanks again

 

[epj3]

Yes, the transmission has software. It needs to know when to shift, what RPM's the engine should be in order to shift, etc.

I think you should take it to the dealer (which very well could be expensive...)