E34 Gurus! Very Rare Problem.. I Need Help I Give Up

[francogt1]

Ok Heres The Deal I BOUGHT THIS CAR WITH THIS PROBLEM THINKING IT WAS SOMETHING SIMPLE, BUT I HAVE NO IDEA NOW.

Lets Start By Talking About The Car.

1991 525i At Transmission
160xxx Miles
Good Condidtion Always Mantained By Jmk Bmw AS FAR I CAN TELL FROM THE RECIPS AND STUFF.



Parts That Been Replced Allready.
New Coolant Sensor, New Fuel Filter,new Exhaust And Cats,air Filter , I've Tryed Swaping Ecu's And It Did Not Solve The Problem It Will Do The Sam,e Thing With The Other Ecu. Afm Is Good Also



Yes I've Tried The Stomp Test And No Codes Are Found At All, Theres No Check Engine Light On At All, also tried disconecting the battery to restet the ecu.







The Problem.



The Car Will Not Rev Past 3000k When Warm It Will Shake And Once You Let Go Of The Gas It Will Then Go Crazy Rev Up And Down And Seattle Down.
When It Hits The 3000k And Starts To Miss And Shake The Check Engine Light Flashes.



When The Car Is Cold It Will Rev Will Like 5000k Basicly The Warmer It Gets The Less It Will Rev When Its In The Normal Temperature It Will Not Rev Past 3k Like Stated Before.

What Are My Options At This Point? Im Very Lost Here I've Been Everywere To See If Anyone Could Figure Out What It Is But No One Can.


Thank You For Taking The Time To Read This


Hopefully Someone Outthere Has A Idea Of Whats Wrong.

Thank You Guys In Advance.


Franco

[GEE e39]

my first thought is the air flow meter
.... be interested to hear how this goes so keep on posting...

[francogt1]

Originally Posted by GEE e39

my first thought is the air flow meter
.... be interested to hear how this goes so keep on posting...

when the car idles, it idlels good actually. i tested the AFM by unpluging it while car is idleing and it does what it should do shakes idles rough ect.

so i dont think the AFM is bad.

am i correct?

[francogt1]

any help here??

[jsncarrier]

My thoughts are o2, maf, or o2 sensor. Maybe even a exhaust leak before the o2 sensor or an intake leak after the maf. But I'm just throwing out a bunch of stuff. Good luck