High RPM Stumble

[Skunkworks]

my 87 325i 5 speed, Has developed a Stumble above 4k and will also stumble on lower rpm as well. I replaced the plugs and checked the wires, still the same symptoms.

the other issue is that it is hard starting when its hot.

[IP2GSR]

I had a stumble at 3500 rpm that turned out to be a faulty AFM. It is worth a try if you can get a spare

[paperplane94]

my 87 325i 5 speed, Has developed a Stumble above 4k and will also stumble on lower rpm as well. I replaced the plugs and checked the wires, still the same symptoms.

the other issue is that it is hard starting when its hot.

This tells me that the Fuel Pressure Regulator is putting in too much fuel, which is probably also causing the stumble.

Probably a tear in the Fuel Pressure Regulator diaphragm.

[FLG]

Hard starting hot is usually temp sensor, intake leaks, or leaky injectors.

Have a smoke test performed, also you could verify sensor by checking it's resistance values and comparing them to spec (no idea what they are offhand)

I'd have a smoke test done first and report back.


Sent from my Galaxy Nexus using Tapatalk 2

[603Racing]

Throwing any codes? It should be.