I Need To Tap Into Your Vast Knowledge Base
 

I Just Got My Cylinder Head Replaced In My 98 528i .....got It Back And It Ran Ok For About Two Days And Then It Started Hesitating And Idling Lower Than It Should..... And When It Is Cold It Takes About 6 Or 7 Tries To Get It To Stay Running.........
What Could This Be..... I Need Your Help.......please .......Thank You

Has the ignition system been serviced?

Does the engine stabilize after a while? Is the check engine light on? What do the exhaust gases look like? Need more info, please.

As Dski mentioned more info needed:

1) Check all your vac lines - connected, cracked, etc
2) Did you reuse spark plugs or install new?
3) Were all head bolts and external part(s) bolts re-torgued when hot?

Also depending on mileage, if you just re-did the head - you might be pulling oil past the rings and oil fouling spark plugs. I'd be looking at things that expand when warm 1st. (vac hoses, gaskets)

125,000 miles
it does stabilze after a while
it use to only hesitate at red lights and stop signs
then it started having instant loses of power for one split second
then quickly recover doing this at 70 mph
the check engine light is on ,I get a abnormal idling reading
it does usually stablize after i get going
my mechanic is checking the fuel system right now.
he thinks maybe since it was sitting up for 2 months
maybe the filter is dried out or something
i going to check everything you guys suggested
thanks for all your help so far
talk to you soon