Why do my plugs keep fouling?


Asked by Mar 09, 2017 at 03:00 AM about the 1987 Chrysler Fifth Avenue Base

Question type: Maintenance & Repair

I have changed coil, plugs, wires, cap and rotor. my fuel economy went from
20mpg to 15mpg , my plugs keep fouling

4 Answers


So judging by your loss in mpg it sounds like it's running very rich, have you checked the codes to see if they lead you somewhere? Could be fuel pressure regulator, O2 sensors, map sensor, one or more of the temp sensors, even a wiring issue, you may need to take it too a shop that has some of the old equipment for the old Chrysler system.


What do the plugs look like when they are fouled? Are the plugs oily wet or sooty wet. Does the car use any engine oil. How many miles on the vehicle? As tennisshoes said above it could be many different things.


the plugs are sooty dry fouled, 57k original on engine, oil is good


Yep way too rich, getting the codes would be the first thing too do.

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