A defective thick film ignition (TFI) module can cause the engine to stall while driving, or the engine may not start. A failed TFI module will require replacement.Google+
Car Problem Reports
Ford E-150 Vehicle Stalls While Driving, or Will Not Start – Engine is Warm
Ford E-150 Problem
Engines Affected: 5.0L V8, 5.8L V8
Average Mileage: 145,000 mi (90,000 mi - 200,000 mi)
Visitor, 1990 Ford E-150, 5.8L V8, 90,000 mi
Engine stalls at let off on road and at idle when hot. Excess gas consumption. Several codes detected. Cked. gas pressure at injector rail and found it was 3 times higher than specs. Changed relay and all is ok.
I have a 90 crown Vic that jus recently started acting up with these same sympoms and havent had a clue as to what it could be I sure hope this is it, I'll be fixing that this weekend and update.