plug in NEWmass air ml wont start unplug mass air truck takes 3 4 5 times to start
 

TAKES 3OR 4 OR 5TIMES TO START TRUCK EVERY MORNING FOR LAST MONTH (99 ML430) ......... TURN THE KEY DONT PRESS GAS AT ALL TAKES 3 OR 4, 5 TO START UP ......RPM GOES UP FOR 5, 6 SECONDS THEN SLOWLY DROPS AND CAR SHUTS OFF AND THEN I START IT AGAIN ......TOOK TO MECH . HE PUT IN NEW MASS AIR STILL DOES IT ........ ........WE BOTH SCRATCHING OUR HEADS ........because if u UNPLUG NEW MASS AIR STARTS FIRST CRANK .... BUT PLUG IN NEW MASS AIR TAKES 3 4 5 TIMES TO START AGAIN ... PS FUEL PRESSURE IS NORMAL PER MECH ...........SO WHATS WRONG HERE ?

Find a new mechanic. Installing a new part without verifying the problem is not how to troubleshoot a problem.

Test fuel pressure, should be approx. 55-60 psi, check cam shaft position sensor at front of right cylinder head

SOME MAF HAVE 2 POWER FEEDS 12 AND 5 V FROM COMPUTER NEED TO HAVE BOF TO WORK MIGHT BE BIG VAC LEAK RUNNING FROM MAP WITH NO PLUG IN MIGHT BE OTHER PROBLEMS NEED TO CHECK

Check your fuel pressure regulator, remove vacuum line at fuel regulator, if fuel dribbles out of vacuum hose replace it, it's on the rail, at front on engine at top

TRUE...... But was the replacement MAF OEM or China with love? If the car runs good with the MAF unplugged it seems to point to BAD MAF.

Running mass with it disconnected will send hfm control module to set mixture to 50% percent reading ie middle of adjustment range, so it sounds like maybe some kind of fuel mixture problem , check for air or fuel issue your better off getting a known good maf and see if its any better than disconecting it, test the wiring to mass etc