[csbarry]

I have a 1996 Escort LX with about 60000 miles on it. About a month ago I began experiencing an intermittent hiccup, went on to become an occasionally diagnosable #4 cylinder misfire, and as of yesterday it seems as though the #4 cylinder isn't firing at all. The only code I get is PO304, indicating #4 cylinder misfire. The car has lost a lot of power. Pulling the spark plug from the #4 cylinder reveals unburnt fuel (spark plug is wet). I have replaced all of the spark plugs and the spark plug wires.

If anyone is familiar with this problem, I would appreciate any help you could give. Thanks.

 

[mark v]

Bad plug wire or coil pack if it has separate coil packs.

 

[Cuda_jim]

My guess is the coil since you replaced the plugs and wires.
Did you do a compression test?

 

[Zephyrman]

Those engines aren't coil on plug, have you checked the cap and rotor? If the #4 peg is burnt, then you need to change out the cap and rotor.

 

[Poppy]

I'm with Zephyrman on this.

If that fails to fix it then the next step would be a compression test.

 

[OlrustysGhost]

I would check the inside of the cap to see if it has a build-up around the contacts. All of them could be cruddy. Scrape the crap off all of them and then try again. if this fixes the problem and 4 starts firing again, go buy a new cap. If not, then I would do the compression test.

 

[csbarry]

There is no cap. The car has an electronic distributorless ignition system. To date the plugs and wires have been interchanged multiple times and last night I put in a new ignition coil module. There has been no change. Cylinders #1 through #3 are firing, #4 isn't and is soaked with fuel. What do think?

 

[mark v]

These cars do not have caps and rotors.

Those engines aren't coil on plug, have you checked the cap and rotor? If the #4 peg is burnt, then you need to change out the cap and rotor.

 

[Cuda_jim]

There is no cap. The car has an electronic distributorless ignition system. To date the plugs and wires have been interchanged multiple times and last night I put in a new ignition coil module. There has been no change. Cylinders #1 through #3 are firing, #4 isn't and is soaked with fuel. What do think?

WAG: Fuel injector, stuck open.
Did you do a compression test?

 

[csbarry]

Broke down and bought a compression tester. Get back to y'all tomorrow.

 

[csbarry]

Compression test was done this morning; bad news. Cylinders 1-3 were as following:180,175, and 187 PSI respectfully. Cylinder # 4 was just 20 PSI. Time to pull the head, unless someone has another idea.

 

[80 maytag]

It wouldn't hurt at this point to get the motor up to operating temp and douching the intake with half a can of seafoam or a quart of water. Rev it up about 2500-3 grand and start trickling it into the air inlet, be careful if you have a mass air sensor , you don't want to get that wet., enough to make the motor stumble but not kill it. You may just have carbon built up on the exhaust valve making it stick open causing your lack of compression.

 

[Cuda_jim]

Compression test was done this morning; bad news. Cylinders 1-3 were as following:180,175, and 187 PSI respectfully. Cylinder # 4 was just 20 PSI. Time to pull the head, unless someone has another idea.

Put around 3-4 oz of oil in the cylinder and do another compression test. If the pressure goes up the rings are bad, if it stays the same the valves might be bad. Could be a head gasket or cracked head too.

 

[Boghog]

After doing a compression check, if one or more of the cylinders tests low, then a cylinder leak down test will help you determine the cause of the weak cylinder. Special equipment (cyl leak down gauge) is required which can be purchased or rented at most auto parts stores. With all the spark plugs removed, rotate the engine so that the cylinder to be tested is on top dead center and ready to fire. This will assure that the valves are closed. Install the leak down gauge in the spark plug hole and apply air pressure. The gauge will register the pressure drop indicating the percentage of leak. In addition, by listening at the exhaust pipe or air intake system or the oil breather you may hear escaping air, which means one of the components, is leaking. Example: air out of the exhaust pipe means the exhaust valve is leaking. By removing the radiator cap and observing the coolant, you can tell if there is a blown head gasket and or a cracked head if there are bubbles.