My cousin called asking advice on his 87 Bronco II that is running very rich. It's been in the shop 4 weeks and the "mechanic has changed most of the sensors, checked fuel pressure and even changed the ECU". It starts and runs but after a few seconds it starts to miss and blow black smoke. It will sometimes clear up for a few seconds but then go back to missing and smoking. The computer does not set any codes. If you pull plugs, all 6 are sooty (he thinks it is multiport injected, but not 100% sure. Air cleaner is on the fender thought) so unlikely a leaky injector.
My first advice was find another shop. If anyone can shed some light on what to check or verify, I'd appreciate it.
Thanks in advance for all responses.
bb