1996 318i 5 speed M44 engine runs on at higher speeds only

[Cape Bob]

96 318IC M44 engine
92,000 miles 5 Speed


Engine runs on at speeds over 65 mph in 5th gear, you take your foot off the accelerator and the mpg (vacuum Gage) does not go to the left right away. It sometimes flutters but never shuts off the fuel right away.

At all speeds below 65 and even above 3,000 rpm it works perfectly. Higher rpm in lower gears than top have no problems.


Things I have done or checked.
Last was change the DISA o-ring, the old was flat in 2 places. Checked the DISA with 12 volts flap snapped shut. Sucked on the vacuum line from the bottom of the valve closed and stayed shut.


Cleaned the throttle body, cleaned the idle air control valve. Engine idles perfectly and runs perfect except on the highway and then only when trying to slow down.


The throttle cable appears to be fine at lower speeds and constant shifting there is no problems so I ruled it out.


I am currently stumped at what the cause could be. Fuel pressure? The fuel filter was changed a bit ago. Nothing had been done to the engine recent to the problem being identified. Any help would be greatly appreciated.