1995 Mustang 3.8 Cylinder 4 Misfire

is it overheating?
any white smoke out the tailpipe?
what does the oil & coolant look like?

do a compression test.

Coolant is green and the oil is dark brown. Compression test was 120lbs. I also put a noid light on the fuel injector and got a good pulse. I shot brake cleaner in the intake and it still missed. Wierd thing to was when I pulled the intake from the throttle body it died.

jaco1224 said:

Coolant is green and the oil is dark brown. Compression test was 120lbs. I also put a noid light on the fuel injector and got a good pulse. I shot brake cleaner in the intake and it still missed. Wierd thing to was when I pulled the intake from the throttle body it died.

Click to expand...

i need compression numbers from all 6 cylinders.

and that's not wierd, that's gonna happen.

As you know your code is a missfire on number 4 cyl, you may have a bad harness that plugs on the injector, crossed plug wires (not likely but can happen) or a bad PCM. Below you will find wiring for number 4 injector as well as your code read out.

http://www.chiltonlibrary.com/content/images/WD/Ford/194/WD_Ford_194642.pdf


Trouble Code: P0304 (3.8L V6 VIN 4 Std)
Cylinder Number 4 Misfire Detected

Print this code data

Number of Trips to Set Code: 2
OBD II Monitor Type: CCM Details
Indicators: MIL Details

• MISFIRE Details
• MIL Details

Trouble Code Conditions:
DTC P0136, P0156, P0171, P0172, P0175, P1130 and P1150 not set, engine started, engine running under positive torque conditions, and the PCM detected a misfire a misfire in Cylinder 4 during the 200 revolution (Catalyst) or 1000 revolution (High Emissions) period. Note: If the misfire is severe, the MIL will flash on/off on the 1st trip!


Possible Causes:

• Air leak in the intake manifold, or in the EGR or PCM system
• Base engine mechanical problem that affects only Cylinder 4
• Fuel delivery component problem that affects only Cylinder 4 (i.e., a contaminated, dirty or sticking fuel injector)
• Ignition system problem (coil, plug) that affects only Cylinder 4
• TSB 02-16-2 contains repair help for this code (LS & T-Bird)
• TSB 03-14-4 contains repair help for this code for COP ignition

If you woulda rode by me on a horse during the rush of 49 and hollered "hey buddy your lookin in the wrong hole" I would have listened. 1 2 4 5 6 are 120lbs or a little better. 3 was at best 5lbs. So the first thing I do now is pull the valve cover and start at the top. But why did the ob2 say it was #4?

jaco1224 said:

If you woulda rode by me on a horse during the rush of 49 and hollered "hey buddy your lookin in the wrong hole" I would have listened. 1 2 4 5 6 are 120lbs or a little better. 3 was at best 5lbs. So the first thing I do now is pull the valve cover and start at the top. But why did the ob2 say it was #4?

Click to expand...

thats exactly what i thought would happen...


your misfire is caused by a compression leak, via a blown head gasket.

Problem solved

Thanks guys. The problem turned out to be a loose rocker arm on number 3 cylinder. I put it back on and it runs fine.

I know this is an old topic. I'm just having the problem. You had code P0304. But fixed rocker arm on Cylinder 3? Is that right?