bucking/hesitating

[MysterE30]

try the coolant temp sensor. ive seen people have these problems (i had it too) and a coolant temp sensor fixed it.

...didnt fix mine but thats besides the point. my problem was that someone decided to not tell me the engine was half way through a 2.7i swap and didnt have the necessary parts..which caused the engine to run like complete ass.

but anyway try the coolant temp sensor. you never know and they're cheap so you might as well try it and knock another thing off the list of things thats not causing the problem...if it doesnt work..

http://www.rmeuropean.com/bmw-parts.aspx#Category

[E30MACK]

tried that....didnt work, ordered the idle control valve so we will see if that does it.

[dlakla1]

I have the same issue, I have put all new fuel pumps,regualtor (adjustable), vacum hoses, plugs,wires , dist cap & rotor, Tested MAF and it seems to be the issue as it does not have a steady rise in resistance as it should. I am going to replace that next and will let ya know if thats the problem....starts and idles fine if I ease onto the gas pedal all seems to be ok, as soon as I pedal it hard it does just as you described. added all new sensors temp etc. Im down to the ECM or MAF ! will keep you posted ! I have the 1986 BMW 325E 2 dr w/2.7 ltr ETA.

[MattPro]

I'm having a really similar problem right now. My car starts fine and runs perfectly for about 10-30 mins depending on how I drive it. After that, it does the same bucking thing then just dies every time I stop. It's really annoying, here's what I've tried so far:
- Checked entire fuel system, everything is fine (fuel pressure is correct when it starts happening, injectors are fine, etc)
- Tried MAF
- Tried ICV
- Tried master relay (suggested by BMW tech, don't know why)

I'll have to try the coolant sensor like suggested, but hopefully someone will solve their problem and the same solution will work for all of us.
It's really frustrating because whenever I try something, I think it worked but then it starts doing it 10 minutes later of driving and I look like an idiot with my car dying at every stoplight.

[Keith M]

The C181 plug? A short there will cause all kinds of issues.

[E30MACK]

whats the C181 plug?

[Keith M]

The connection between the fuel injection wires and the main harness. It's located under the intake manifold.

[Ryann]

If the tach doesn't move during an event but the econometer drives towards zero, look to the fuel system (bad relay, fuse, FPR, filter, pump).

The contacts in my AFM wore a groove through the resistor/contact surface, causing bucking and MPG meter dips toward zero. I was getting an AFM code with the stomp test and fixed it using instructions from this video:

http://www.youtube.com/watch?v=-11J8XawQtc

[E30MACK]

tried the idle control sensor and it didnt help at all.....next?

[MattPro]

From the Bentley manual:

[E30MACK]

so the elimintion process continues.....

[E30MACK]

I just changed the fuel pressure regulator and thats not it either....damn it