please help... problem in high speed is it fuel pump or fuel filter

[thunderbird815]

Hello

yesterday i took my 1991 525i and fix the heat problem but i got the following priblem right after i got back to home.

in high speeds the engine start bumping and i cant accelerate any more. i have asked a friend and he told me that its mostly the fuel pumb or the fuel filter. as for the filter i have replaced it and it was so dirty but the problem still exsists... any ideas help please could it be the fuel pump.

[strad]

The obvious answer is to run the fuel delivery tests outlined in Bentley and see how your fuel delivery system stacks up against spec. Don't continue to throw parts at the problem without proper diagnostics.

If you find that the fuel system performs to spec, well then you can look at other things.

[thunderbird815]

can u give me any appliable hint we dont have the required test tools in my country thank you