98 750il fuel delivery problem

[rduncan07]

Hello all this is my first post,

I am looking for help with a problem with my 750il.
My car has the following symptoms:
-Random Misfire when cold, then runs poorly. Car can be pulled over turned off then back on and everything works as it should.
-Hesitancy when accelerating. The drop down switch takes awhile to fully engage the engine.
-Raw smell of gasoline until car warms up. Visual inspection showed no leaks.
-If car is going less than 20 mph you can let go off gas pedal and the car will maintain that speed. Also when braking the MPG meter goes down to 8 and then goes back to 40 where it should be.

I have done the following repairs:
-Intake Manifold Gasket Repair
-Fuel lines from tank to motor bay
-Fuel lines under manifold
-Fuel injector Gaskets
-Checked MAFs and resistance is within range

I would greatly appreciate any tips or ideas anyone has.

[David325e]

Does the BMW fuel gauge (you're talking about the one under the tach, right?) measure manifold vacuum as the means of engine efficiency?

Does your brake pedal sink eventually when held?
Does applying the brakes at idle cause the engine to stumble, or almost stall?
Have you checked for air leaks?

I'm going to bet you have several vacuum leaks. Especially involving the brake vacuum booster. What kind of mpg's are you getting? Any significant change lately, if you've owned the car for awhile.

[S.Hafsmo]

The fuel gauge uses the signal given to the injectors from the DME, telling them how long to stay open at each stroke.
As well as the speedometer of course.

[IcemanBHE]

Welcome to the forum. :)

[Mayorchuck]

Welcome home.