Need help……1992 Classic 3.9L V8 starts when cold, runs smooth for approx. 15 minutes until hot then starts to run ruff until it finally stalls. Will barely restart. No power at all. When placed into gear, really barely runs. Exhaust really smells. No Check Engine Lite, no codes. New distributor, fuel pump, fuel filter, replace air flow sensor, no change… Any ideas?

 

Check fuel pressure regulator and the vacuum line connected to it. Cracked vacuum line or broken fuel pressure regulator diaphragm causes a rich condition at idle.

With the engine off, apply vacuum to the FPR and see if it holds.

Also look at oxygen sensors.

 

Check the catalytic converters as well see if they are glowing cherry red.