1996 crown victoria misfiring loss of power under light to heavy acceleration, rough idle

A flashing light usually means exhaust related

If the CEL is flashing, the cause of this feeling is undoubtedly an engine misfire. On a Crown Victoria, the CEL only begins to flash when a misfire is detected. Too much misfiring can damage the catalytic converter. This is a warning designed to avoid said damage.

Compression check may tell you something.

P0304 means that cylinder 4 has a misfire and P0305 is a cylinder 5 misfire. What this means is you may have bad spark plugs, or bad plug wires, or you may need to replace your distributor cap and rotor. I would start with plugs and wires.

Misfire is a common driveability problem that may or may not be easy to diagnose, depending on the cause. A misfiring cylinder in a four-cylinder engine is, pardon the pun, hard to miss. The loss of 25% of the engine's power output is the equivalent of a horse trying to run on three legs. The engine may shake so badly at idle that it causes vibrations that can be felt in the steering wheel and throughout the vehicle. The engine also may be hard to start and may even stall at idle, depending on the accessory load (air conditioning, headlights and electric rear defroster, for example).

When misfire occurs, performance suffers along with fuel economy, emissions and idle quality. And, when a misfiring vehicle is subjected to an emissions test, it will usually fail because of the unusually high levels of hydrocarbons (HC) in the exhaust.

What causes a cylinder to misfire? Basically, it's one of three things: loss of spark; the air/fuel mixture is too far out of balance to ignite; or loss of compression. Loss of spark includes anything that prevents coil voltage from jumping the electrode gap at the end of the spark plug. Causes include worn, fouled or damaged spark plugs, bad spark plug wires or even a cracked distributor cap. A weak coil or excessive rotor gas inside a distributor would affect all cylinders, not just a single cylinder.

"Lean misfire" can occur when the air/fuel mixture is too lean (not enough gasoline in the mixture) to burn. This can be caused by a dirty, clogged or inoperative fuel injector; air leaks; or low fuel pressure because of a weak pump, restricted filter or leaky pressure regulator. Low fuel pressure would affect all cylinders rather than an individual cylinder, as would most air leaks. A leaky EGR valve can also have the same effect as an air leak.

Loss of compression means the cylinder loses most of its air/fuel mixture before it can be ignited. The most likely causes here are a leaky (burned) exhaust valve or a blown head gasket. If two adjacent cylinders are misfiring, it's likely the head gasket between them has failed. Also, if an engine is overheating or losing coolant, it's likely the head gasket is the culprit.

Intermittent misfires are the worst kind to diagnose because the misfire comes and goes depending on engine load or operating conditions. They seem to occur for no apparent reason. The engine may only misfire and run rough when cold but then smooth out as it warms up. Or, it may start and idle fine but then misfire or hesitate when it comes under load. Also, it may run fine most of the time but suddenly misfire or cut out for no apparent reason. Intermittent misfires can be a real challenge to diagnose, so let's start with a steady misfire in one cylinder before moving on to intermittent misfires.

Hope this help.

Ahhhh!, if only we could turn back the hands of time. Is the vehicle sending any signals like blue smoke through the exhaust, or using a lot of oil. Possibly running on after the ignition is turned off.These are all indications of high milage wear internally. Rings, bearings, etc.etc. Low oil pressure? Blinking oil light when at intersections. Any of the above?

I found this; if it helps.
The injectors need to be cleaned, if an engine is experiencing any of the classic symptoms of dirty injectors, such as lean misfire, rough idle, hesitation and stumbling on light acceleration, a loss of power, and higher hydrocarbon (HC) and carbon monoxide (CO) emissions.
Lean misfire may also trigger a misfire code and turn on the Check Engine light on 1996 and newer vehicles with OBD II systems. The code often will be a P0300 random misfire code, or you may find one or more misfire codes for individual cylinders, depending on which injectors are most affected.

the web page was:
http://www.aa1car.com/library/2003/ic30336.htm

Hope this helps

I just came up with that exact issue in my 2003 with 98K police crown vic. And the last time I had this issue in a 2001 police Crown vic it was the crank shaft position sensor. A $20 part and about 30 mins to put it in. located near the bottom of the engine. I had to un bolt the A/C compressor and push it out of the way a few inches to get to the sensor. If you have about 100K mile on it and its an idled heavy police car, this sensor should be changed out anyway. It can leave you on the road dead and some dealers have a hard time find out whats wrong as the OBD 2 does not see it as a problem when it goes bad or becomes touchy as I think mine is.

usaly plugs & wires but I would get that coil tested before I do wire and spark plugs! if coil is good wire and plugs! hi milage???

not coil coil it wouldnt fire at all it is either a plug or a wire replace the wire and plugs and that will fix it