OK I've been having an occasional P0170/P0173 (Merc 2017/2086) " (at idle speed). Enrichment over permissible limit" both banks.

Today for the first time I observed it: fully warmed up at a stop light the instant fuel trim on both banks went into 20's (usually around 3) bank 1 first followed by bank 2. As soon as left light it came right back down. Fuel pressure is 58, replaced MAF, replaced O2 sensors, checked for hose issues (but a vaccuum leak would make it go lean, not rich). About the only thing I can think of at this point is a leaky injector but not sure how a bank 1 injector would affect bank 2. Anyone have a different idea ? I do not have enough hair as it is.

 

Methinks you are thinking bass-ackwards on this. A +20 reading on the instant trim means the computater thinks the engine has gone severe lean and it's commanding extra fuel to compensate.
Vacuum leak is back in the equation.
( Thanks to Eric O at South Main Auto for splaining this to me in his videos )

 

Sorry that is negative 20's - thinks it is over rich. 171 & 174 would be very lean.

When I come to a stop in drive I can just see both banks ramping up. Bank 1 first then bank 2. Did not see it ramping like that until I added some Techron cleaner to the gas.

 

Well, that's different. Never mind.

 

What is a good source for a set of injectors please ?

 

I would think Rob at Needswings .....