I recently bought a 91 brougham 5.7 with 105k miles. At first it ran ok then it started missing at light pedal under load and ran even worse at full throttle almost to the point of stahling if you don't let off the gas. So I changed the following; cap,rotor,sp wires and plugs,air filter,fuel filter,exhaust from the cat back. Still it ran the same, crappy! So I retrieved the codes and got rich o2 sensor ans evo sys failure. Replaced o2 sensor and still runs the same. Also I tried to clear the codes per procedure and they would't clear. No check engine light. Good comp on all cyl. Previous owner told me it's been doing this on and off for 2 yrs since about 95k miles. What do you guys think computer problems,electrical or what? Please help the car has a app on tues. but I really want to fix it myself,it's driving me nuts! Thanks-Black Deville

I recently bought a 91 brougham 5.7 with 105k miles. At first it ran ok then it started missing at light pedal under load and ran even worse at full throttle almost to the point of stahling if you don't let off the gas. So I changed the following; cap,rotor,sp wires and plugs,air filter,fuel filter,exhaust from the cat back. Still it ran the same, crappy! So I retrieved the codes and got rich o2 sensor ans evo sys failure. Replaced o2 sensor and still runs the same. Also I tried to clear the codes per procedure and they would't clear. No check engine light. Good comp on all cyl. Previous owner told me it's been doing this on and off for 2 yrs since about 95k miles. What do you guys think computer problems,electrical or what? Please help the car has a app on tues. but I really want to fix it myself,it's driving me nuts! Thanks-Black Deville
Were you able to clear the codes or not? Could be dirty/bad injectors? There are other members here who could further assist you as I am not familar with the newer Broughams. Good luck.

Could be the fuel pump, or fuel related. Have you check the fuel pressure.


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