This sounds an awful lot like the problem I had with my '88 351. It all started with a bad pressure reg. , which dumped the stock hi pressure fuel pump. I didn't know about the regulator, so I just replaced the pump with a NAPA brand (good parts). That worked just fine until the fuel pump was pressurizing the fuel system to over a hundred pounds. That leads to leaky injectors. Fortunately, the guys down at the wrecking yard sold me an entire intake with fuel rails and injectors that didn't leak for $75 bucks. The lowest price I found for new injectors was $70 each. To make a long story short. It is worth the $40 to buy a fuel injection pressure gauge and see exactly what your fuel pressure is doing. Key on it should pressurize to about 35#. I think there is a timer for that function. Then start, it should maintain about 35# at all rpm's. It might flucuate a little but I think +/- 10 % is probably O.K.
Hope it helps,
Rick
