Left and right bank running rich | Ford Explorer Forums - Serious Explorations

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Left and right bank running rich


New Member
March 8, 2010
Reaction score
City, State
Vacaville California
Year, Model & Trim Level
1999 4x4 Explorer 4.0 OHV
I have a California sold 1999 ford explorer with a 4.0L OHV engine. Apparently the injectors were a lower flow rate then the rest of the united states and I recenlty changed the injectors with standard higher flow injectors and I am getting a left and right bank rich light. How can I get this vehicle to run right with the new injectors? Buy an ECM from a non-california explorer or have the current ECM re-programmed? I don't want to buy injectors again and the old ones are not re-usable. Thanks for your help.


Since you still live in California, it may be illegal for a dealer to reprogram your PCM for the higher flow injectors. One alternative is to purchase an SCT X3 with a tune for your configuration. If you purchase a non-California PCM you might run into PATS issues which I am not knowledgeable on.