1987 BMW 528e 5 speed manual transmission dies while I am driving. It occures when I slow down, in traffic, or when I depress the cluch. I try to restart and it seems to hae a very bad miss. I have to slow down with the hand brake and keep the engine at high RMPs to avoid the car from stalling. I have changed the sparks plugs twice. Can you help me?
So using the regular brakes causes a problem? My guess would be a vacuum leak somewhere.
Just think. Where does the throttle plate go when you take your foot off the gas pedal? If you said, “To the idle position.”, you’d be correct. Check the performance at idle (throttle position, and, engine speed). Spray clean the throttle bore and throttle plate with carb cleaner. Use a vacuum gauge to check intake vacuum.
You may want to check the PCV valve as well. You may also have a clogged fuel filter or air filter. You may also need to check your ignition timing and your timing belt/chain(don’t know what you have). Did you change your plug wires when you changed plugs? 1 bad wire could also do it.