I pressurewashed the engine to my 2000 grand marquis and now it is running rough and idleing rough as well what do I do now

Asked by Jan 27, 2017 at 06:49 PM about the Mercury Grand Marquis

Question type: Maintenance & Repair

5 Answers


Remove the engine coils one at a time and dry out the spark plug wells. While you are at it install new plugs and seal the coil boots with dielectric grease. NEVER wash a Triton engine or you will have this problem.


You could have gotten water under the plug wires, in the coil pack, short the oxygen sensors, do you have a leaf blower, start that up and blow the hell out of it. Look uder the fuse and relay box. Let it dry a few day with the hood up.....

1 of 1 people found this helpful.


1 of 1 people found this helpful.

There are 8 coils and the spark plug wells are designed to collect water. I know because I used to wash my truck engine - no more.

1 of 1 people found this helpful.

You said it F O R

1 of 1 people found this helpful.

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