True could have a weak fuel pump under heavier loads/demands

:iagree:

Got an appt. on Friday at the local dealer.. will post an update for anyone else having the same problem..

Partially collapsed catalytic convertor? Need those O2 readings.

2002 X5 3.0 314,600 miles
2014 4281 24,300 miles

2004 325i sold at 123,600 miles
2001 325i sold at 66,000 miles

1970 Firebird - Under restoration

A fuel pressure gauge is cheap quick tester.
Example: https://www.amazon.com/OTC-5630-Fuel...ressure+tester

Or a block exhaust system could also be the problem. In my younger day, I had an OPEL 1900 that couldn't get out of the way of a bicyclist until one day I removed the exhaust. What a different that made. It felt like I dropped a V8 in that 4 bangers.

Remember an engine is nothing but an air pump. It can only breathe as much air as it exhaust.

Some auto parts store rent fuel pressure gauges, rent fee is returned when gauge is returned. Some will test it for you.

FYI, cleaning doesn't eliminate MAF, doesn't always work and problem could be connector. Did you use MAF cleaner, spray liberally, in particular the wires that are not readily visible in the sensor?

Have you checked for error codes?

:iagree:

Air in, Air out. It has to have somewhere to go :rofl:

So dealer diagnosis is: bank 2 pre cat o2 sensor, vanos solenoid... they also said to replace spark plugs but they are new ngk's, and coils as well. Not sure how good their diagnosis is.. regarding the plugs...dont even think they removed them.