On this system there are "trigger" points in the distributor that send dwell signals to the EFI computer & it will pulse 2 injectors at every stroke.
Cylinders 1 & 5 are on one set. The other pars of cylinders are 4/8, 2/7, & 3/6. IF you are losing any pair then the trigger points could be the problem. Many times oil will push thru the distributor and cause this problem.
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