(newb) Loss of power going uphill NEED ADVICE

[jpsamson27]

Hi, Im new to this forum, and new to BMW ownership. I bought my 90 525i 3 months ago and i am having a couple of issues with it and could really use some advice. First i have a hot start problem (which with this forum help) i think it is either a fuel check valve or leaking injector. But the problem that is really driving me nuts is when i drive faster then 60mph and mostly when im going uphill the check engine light goes on and i have big loss of power. If a put the clutch in and rev it to around 5000rpms the check engine light will go off but it doesnt take long for it to come back on. When i code the check engine light it tells me that it is my O2 sensor, but i think that the O2 sensor is just a sympton of the main problem maby mass air flow sensor. Any advice or ideas would be really helpfull. THANX A BUNCH 4 YOUR TIME

[motorman]

Hi, I'm a newby too, interesting problem, you could be right about the maf, my 1st bmw was a e28 528i, it had a sticky flap in the maf, it would experiance a loss of power when warm and under pressure (ie load,or hills). Or you have only had the car a short while, try changing the fuel filter, it may be partially blocked (should be changed every 12 months), but this doesn't explain the engine check light comming on and off. 02 sensor is not used by the injection system when the car is under excelleration when the engine needs an enriched fuel mixture, but is used to moniter the air/fuel ratio when cruising to maintain a ratio of about 12.5 to 1, but with the number of K's it needs checking or replacing. Hope this helps

[jpsamson27]

ttt