Qx4 falls on its face past 40 mph??????

[infinitiwon]

Please help. Any ideas??? Just replaced maf sensor and its alot better until 40. I dont understand. I can get a passing gear from 45 to 70. But 0-60 is like 15 seconds. 0-40 is 6secs.??????????????????????????????

[VG33QX4]

No check engine light? What about pending codes. Sounds like it's pulling timing.

[infinitiwon]

Still have ses light so i am leaving battery disconnected overnight to see if that clears it. 2001 qx4 150k replaced maf tonight. Any suggestions would be great.
THANKS

[VG33QX4]

you need to:

scan it but since you reset the ecu you wont have a code for a little while
check the timing with a light or with a scanner 8-10 at idle around 30-40 cruising at highway speed
probably a camshaft or crankshaft sensor, or at the least put a fuel filter in it

[Towncivilian]

I would also suggest fuel filter to begin with. There's an excellent guide here to help you through the process of replacing it.