1999 Ford Crown Victoria Just had new intake manifold insta

[quote:eb232bea1c="[email protected]"]Engine Performance problem
1999 Ford Crown Victoria V8 Two Wheel Drive Automatic

my manifold was just replaced ran smooth before runs rough now. it was replaced becaus of a crack by the thermostat that had caused a leak. shop says it could be one of the coils is be bad due to getting wet from coolant, please advise Thanks Thomas[/quote:eb232bea1c]


Hi Thomas,

Is your check engine light on? If so go by your local auto zone and have them pull codes. Post them here in forum. If it is a coil and the cylinder is misfiring then it should set a code and the code will pinpoint the cylinder # that is misfiring.

Once you find out which cylinder is misfiring pull plug and see what it looks like if it is wet with gas then it is most likely the coil. If wet with coolant mostlikely intake gasket slipped while installing and got damages causing the problem.

no check engine light, and the car seems to have smoothed out? If it is a coil will the check engine light always come on?

[quote:a173a6de8e="[email protected]"]no check engine light, and the car seems to have smoothed out? If it is a coil will the check engine light always come on?[/quote:a173a6de8e]


Yes, if you have what is called coil over, which is, you have a coil for each plug or a coil pack which is a group of coils and one goes bad it will set a code and turn engine light on.

A cylinder Misfire will set a code and turn engine light on. It doesn't neccessarily mean it's a coil causing the misfire. A misfire can be caused by a bad injector, plug wire, plug, injector harness and few other things. And to pin point the cause is a matter of diagnosis.