Ruff Engine Idle

Hello fellow members,

Got another question for you, This may be easy for you veterans. Before I start to dig into a lot of replacing parts I will see if I can tap your brains…

I have a ’88 300 SE with 230,000 miles on it. In the mornings or even when it sits for a while, when I start it, the engine will run ruff for about 30 to 60 seconds. Then it seems to line out and run great. I don’t have problems with accelerating, normal driving, or curb idle. Just when I star the car. It is more so in the morning than during the day. I try to turn the key and wait until the buzzer quits (just used as a timer) then start the car. It seems to help. Makes me think that I am loosing fuel pressure in the lines…don’t know… Any Ideas before I start replacing everything?

Do a search under OVP relay or rough idle. See if any of the threads describe what your car is doing. I am almost 100% sure it is the OVP.

Doesn't sound like the OVP relay. If it fails cold starting would be very difficult and there would be no idle speed control.

It sounds more like a fuel pressure issue - possibly an internal leak from the accumulator or pressure regulator, so they won't hold pressure after shutdown, and it takes the 30-60 seconds for the pump to build up full pressure against a high leak down rate.

Duke