My 91zeder was running rich,rough idle and service engine light would come on. Had the code tested (rich exhaust) and 4out of 8 injectors were ohm tested to be no good.
Replaced all 8 injectors with 19lb/hr Ford Motorport injectors 3 days ago.Engine runs very good, idles nice and pulls hard at WOT.
But today as I'm cruising down freeway the service engine light came on again Any ideas?

 

You can pull your own codes with a paper clip

Find out if its rich again or not, it may even be lean this time.

Then go from there.

 

Chances are that you are lean now. I have the same injectors on
a 350 and am running them at 52lbs.