Cessna 340 pilot reported an engine failure due to improper fuel system operation.

Attributes
ACN	1596302
Time
Date	201811
Local Time Of Day	0601-1200
Place
Locale Reference	ZMP.ARTCC
State Reference	MN
Environment
Flight Conditions	Mixed
Light	Daylight
Aircraft 1
Make Model Name	Cessna 340/340A
Operating Under FAR Part	Part 135
Flight Phase	Initial Approach
Route In Use	Vectors
Flight Plan	IFR
Component
Aircraft Component	Fuel Selector
Person 1
Function	Pilot Flying Single Pilot
Qualification	Flight Crew Flight Instructor Flight Crew Instrument Flight Crew Multiengine Flight Crew Commercial
Experience	Flight Crew Last 90 Days 112 Flight Crew Total 4486 Flight Crew Type 377
Events
Anomaly	Aircraft Equipment Problem Less Severe Deviation - Altitude Excursion From Assigned Altitude Deviation - Procedural Published Material / Policy Inflight Event / Encounter Fuel Issue

Narrative:

I was transferring fuel from aux to main noted 10 gallons left; then began to get vectors to final xx after changing approaches from [runway] xy; at which time was busy setting up for the approach when right engine fuel ran out I immediately switched back to the main; right engine did not start back up as soon as I had expected. I told center I lost right engine and they gave me priority on approach. At that time I think I dipped below altitude by a couple hundred feet and not sure if I drifted off course but I promptly got back to altitude and on course; at that time the engine came back and I continued down ILS to runway xx and told center we were on the ground safe.

Original NASA ASRS Text

Title: Cessna 340 pilot reported an engine failure due to improper fuel system operation.

Narrative: I was transferring fuel from aux to main noted 10 gallons left; then began to get vectors to final XX after changing approaches from [RWY] XY; At which time was busy setting up for the approach when right engine fuel ran out I immediately switched back to the main; right engine did not start back up as soon as I had expected. I told Center I lost right engine and they gave me priority on approach. At that time I think I dipped below altitude by a couple hundred feet and not sure if I drifted off course but I promptly got back to altitude and on course; at that time the engine came back and I continued down ILS to Runway XX and told Center we were on the ground safe.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.