Code P0304 apperas on the scanner - 2000 Ford Taurus

I would say you have more that one code fault and they just used a cheap scan tool. You need an auto electrician with a pro grade scan tool computer. That is the only thing that can diagnose the engine speed sensor.

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What the P0304 code means. The P0304 code will be seen in cars where the ECU has detected that cylinder 4 is not firing properly. The ECU monitors the operation of all cylinders to ensure they are all firing on time, so when one misfires repeatedly, a Check Engine Light is set.

P0304 OBD-II Trouble Code: Cylinder 4 Misfire Detected

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It is one of the two. First thing is to remove and check the plug for gap and condition. Then reset the code and run the vehicle. If it does it again, you swap the coil pack from Number 4 to Number 1. If the misfire them moves to number 1 you know the coil pack is the issue. Sometimes just moving it will fix the issue as the connections get remade.

Swap the #4 coil with #3, swap #4 spark plug with #2 and swap #4 injector with #1. Clear codes. Drive the car until it has a misfire code, again. If you get P0303, it's a bad coil. If you get P0302, it's a bad plug. If you get P0301, it's a bad injector. If you get P0304 again, it's a mechanical engine problem, like a burned valve, bad intake manifold gasket, worn cam, etc. or a wiring harness issue to the coil or injector, maybe even a bad computer.

The P0304 code means that the cylinder 4 is misfiring or is ... P0304 MAZDA P0304 ... Engine Light ON? The Engine-Codes.com ELM327 WiFi Car Diagnostic
OBD II Trouble Code Information and Diagnosis Engine Codes com Welcome to Engine Codes

A P0304 code means that the the car's computer has detected that one of the engine's cylinders is not firing properly. In this case it's cylinder #4.

A code P0304 may mean that one or more of the following has happened:
Faulty spark plug or wire
Faulty coil (pack)
Faulty oxygen sensor(s)
Faulty fuel injector
Burned exhaust valve
Faulty catalytic converter(s)
Running out of fuel
Poor compression
Defective computer

Contact us if need additional details or clues to solve it.

From www.hondasuv.com:

 

The P1399 random misfire along with one or more of these codes: P0301, P0302, P0303, P0304 -- indicates a problem with the valves. The B20 engines in the 1997-2001 CR-Vs are known to have problems with valves tightening and then 'burning'.

So the first question is when was the last time you adjusted the valves? If you don't know or never have, then have them adjusted. Soon...

P0304 indicates misfire in the cylinders..
A misfire can be triggered by several situations. inadequate fuel, ignition misfire, insufficient air flow, too much fuel, incomplete compression... If you look at freeze frame data with a scanner you can see what the conditions were when the code was set, this will really help to pinpoint the problem.

I have an 2002 Kia sedona the code p0304 means an 4 cylinder misfire and also the wiring and plugs.I noticed an while back that when I press the gas smoke will come from my tailpipe and now my van is hesitating to go and it stumbles and the check engine light is on,I have the same code p0304.

P0304 means that you have a misfire on cylinder #4.Pending code are secondary indicators to let the mechanic know that the problem is more or less constant even if it is a random missfire.

all the codes you have are all related to the fuel trim, this problem needs to be looked at with a european capable scanner for futher tests sorry.