Stumbling after its hot and starting off.
Its a 84 528e standard shift.
Every now and then my wife tells me she will start off and it will just stumble like no gas is getting to it. Might happen once a month or go for months and do fine. Sometimes she will turn right off the main road to our road and down shift and when she goes to give it gas it might stumble. Never have figured that one out and checked every thing possible. that has been going on for years!!!!!!!
What happened last week has got me baffled. She had to go out of town. 145 mile trip. The longer she drove and parts got hotter the stumbling from starting off Begin and once she got it going it would do fine.
After letting the car set for 3 hrs or more then it did great and no sign of a problem. When she started back home then after all was heated back up again it started back. She had to get behind something taking off slow at a light to get it going and then on the open road it did fine. I wish she had got on it harder to see if it would try to stumble at 60 because that might have gave me a little more to go on.
I took it for a test drive a day latter and all worked great as normal as I expected.
The pump in the tank was replaced a few years ago along with a new pressure regulator.
The out board high pressure pump was replaced in 98 but the car set for a few years and can't find a receipt for one if I replaced it again. I do try my best to keep everything for it.
The hight pressure pump the last time I tested it was doing fine. But it has always buzzed loud. That could be because the rubber around it is getting old and you just hear it more?
What I am wondering if when the car has been running for a long time is that pump is getting hot and not keeping the pressure high enough for the car to accelerate?
I wish it had the fuel rail port on it like the newer ones do. It would make things a lot eaiser to test.
If any of you have any other ideas that I might be over looking just let me know.