Question about 2002 Mercedes-Benz C-Class

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P0304 replaced maf ran good and then got p0304 changed injector still has same code i erased code disconnected coil showed miss then when check eng light turns on there is no response

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Hi there:
DTC P0304 Code - Cylinder #4 Misfire Detected
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.

Symptoms may include:
the engine may be harder to start
the engine may stumble / stumble, and/or hesitate
other symptoms may also be present

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

Possible Solutions:
If there are no symptoms, the simplest thing to do is to reset the code and see if it comes back.

If there are symptoms such as the engine is stumbling or hesitating, check all wiring and connectors that lead to the cylinders (i.e. spark plugs). Depending on how long the ignition components have been in the car, it may be a good idea to replace them as part of your regular maintenance schedule. I would suggest spark plugs, spark plug wires, distributor cap, and rotor (if applicable). Otherwise, check the coils (a.k.a. coil packs). In some cases, the catalytic converter has gone bad. If you smell rotten eggs in the exhaust, your cat converter needs to be replaced. I've also heard in other cases the problems were faulty fuel injectors.

Hope this helps; also keep in mind that your feedback is important and I`ll appreciate your time and consideration if you leave some testimonial comment about this answer.

Thank you for using FixYa, have a nice day

Posted on Feb 24, 2012

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Car sputtering badly. Codes P303 n P102 show on diagnostics and have replaced both parts associated with these codes,PLUS, new fuel filter, engine still sputtering badly.


Hi,

I hope I can help with this. This could mean the engine spark plugs or plug is the issue. Also check the exhaust pipe. White smoke indicates a coolant issue. Check your coolant reservoir. Black smoke indicates a Fuel issue. Blue is an oil issue. Also, speaking of your spark plugs there very well could be a misfire.

the code P303 could be cylinder 3 misfire
P102 the mass air flow sensor which is on the air filter cover. It's an electrical part and is sensor. Please check these and let me know.

Jul 28, 2016 | Cars & Trucks

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How can I be sure if my PCM is bad???


I would try disconnecting battery again. Disconnect both cables and touch them together for a few seconds. This will reset all modules. Wierd that you had so many codes after just disconnecting battery. Sometimes very hard to tell if ecm is bad.

Dec 01, 2014 | 2006 Pontiac Torrent

1 Answer

Misfiring. Error codes p0306, p0351, p0352


p0306 refers to cylinder 6 misfire detected===causes engine mechanical fault--wiring---ignition/fuel system--injector ---ECT/MAF sensor---ECM
IF there was a mechanical fault (hydraulic follower ) or valve it would be there most of the time and not just on start up. Possible injector fault but I would be inclined to check out the MAF sensor codes p0351 &2 refer to ignition coil A and ignition coil B primary /secondary--circuit malfunction === causes --wiring--ignition coil--ECM ( all causes for the both)
going on this check out the coils and check that the wiring and connections are clean and tight. basically I would be inclined to change out the coils and check /replace the MAF sensor.
change the engine --sounds like advice to get some extra money out of you.

Apr 27, 2014 | 2005 Ford F-150

2 Answers

P0304, p0305, and p0306 on 02 Mustang 3.8l.


The page LINK here is the best i have read on misfire diagnosis, it is protected so I can't copy it but you can go to the link.

Jun 29, 2012 | 2002 Ford Mustang

2 Answers

Why does p0304 appear when engine warms up on 2002 c240


Seems to be a misfire code, you could have a partially clogged injector. You can have them tested at a local car shop.

Feb 09, 2012 | Cars & Trucks

1 Answer

How to fix p0304 on 2002 c240 mercedes


Hi there:
DTC P0304 Code - Cylinder #4 Misfire Detected
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.

Symptoms may include:
the engine may be harder to start
the engine may stumble / stumble, and/or hesitate
other symptoms may also be present

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

Possible Solutions:
If there are no symptoms, the simplest thing to do is to reset the code and see if it comes back.

If there are symptoms such as the engine is stumbling or hesitating, check all wiring and connectors that lead to the cylinders (i.e. spark plugs). Depending on how long the ignition components have been in the car, it may be a good idea to replace them as part of your regular maintenance schedule. I would suggest spark plugs, spark plug wires, distributor cap, and rotor (if applicable). Otherwise, check the coils (a.k.a. coil packs). In some cases, the catalytic converter has gone bad. If you smell rotten eggs in the exhaust, your cat converter needs to be replaced. I've also heard in other cases the problems were faulty fuel injectors.

Hope this helps; also keep in mind that your feedback is important and I`ll appreciate your time and consideration if you leave some testimonial comment about this answer.

Thank you for using FixYa, have a nice day.

Feb 09, 2012 | Dodge Caravan Cars & Trucks

1 Answer

Ihave a code 306 i unplug the fuel injector and no change in the eng rpm keep missing do i have a bad injector


You could, but I would also check, spark plug wire's and ignition coil pack, and if that checks good, do a cylinder compression test, if all good replace fuel injector then.

Sep 09, 2010 | 2002 Ford Ranger Regular Cab

1 Answer

I have 97 cavalier with 148,000 miles 2.4l dohc went to do my smog check n show has a code po304 cylender 4 is misfire the guys did a compression test on the cylender showed 65 psi only. the car had new...


P0304 Code - Cylinder #4 Misfire Technical Description Cylinder #4 Misfire Detected
What does that mean? 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.
FB.init("dd7d9e9681341cde77587bc6a2029f6f"); OBD-Codes.com on Facebookcopyscape.gif SymptomsSymptoms may include:
  • the engine may be harder to start
  • the engine may stumble / stumble, and/or hesitate
  • other symptoms may also be present
Causes 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
Possible Solutions If there are no symptoms, the simplest thing to do is to reset the code and see if it comes back.
If there are symptoms such as the engine is stumbling or hesitating, check all wiring and connectors that lead to the cylinders (i.e. spark plugs). Depending on how long the ignition components have been in the car, it may be a good idea to replace them as part of your regular maintenance schedule. I would suggest spark plugs, spark plug wires, distributor cap, and rotor (if applicable). Otherwise, check the coils (a.k.a. coil packs). In some cases, the catalytic converter has gone bad. If you smell rotten eggs in the exhaust, your cat converter needs to be replaced. I've also heard in other cases the problems were faulty fuel injectors
.

Feb 01, 2010 | 1997 Chevrolet Cavalier

2 Answers

I have had a Check Engine Light on my dash for a good 3 weeks. I noticed the Van running really ruff. I took the van to autozone and got the codes ran. The code of P0303 (cylinder 3 misfire) came back...


well the first thing you should do is check the compression in cyl number four the compression should be within 5-8 of the nearest cyl if you see a significant diffrence in pressure you have a week cylinder...also is there any discoloration on the number 4 spark plug a coolant soaked or fuel soaked spark plug can lead u in the right direction..lastly i would take a look at the exact fuel pressure you will need a gauge and take a look low or high fuel pressure can cause a misfire....keep in mind that a clogged catylitic convertor can also cause a misfire do to accesive back pressure give your convertor a tap and see if its rattling ....hopefully this can lead u in the right direction ...good luck

Nov 30, 2009 | 2001 Dodge Caravan

3 Answers

Check engine light


A multi misfire may mean that one or more of the following has happened:
Faulty spark plug or wires, Faulty coil (pack), Faulty oxygen sensor(s), Faulty fuel injector(s), Stuck/blocked EGR valve / passages, Faulty camshaft position sensor, Defective computer.

The engine is stumbling or hesitating, check all wiring and connectors that lead to the cylinders (i.e. spark plugs). Depending on how long the ignition components have been in the car, it may be a good idea to replace them as part of your regular maintenance schedule. I would suggest spark plugs, spark plug wire, distributor cap, and rotor (if applicable). Otherwise, check the coils (a.k.a. coil packs). In some cases, the the problems were faulty fuel injectors. 

Random misfires that jump around from one cylinder to another (read: P030x codes) also will set a P0300 code. The underlying cause is often a lean fuel condition, which may be due to a vacuum leak in the intake manifold or unmetered air getting past the airflow sensor, or an EGR valve that is stuck open.

Good luck and hope this information helps, keep me posted, be glad to help you get the truck running 100% again. Not sure if your running a K&N air filter, and if you are there may be a flim of oil on the MAF sensor that is making you run lean. You may want to spray down the MAF sensor with a can of MAF cleaner. 

Jul 02, 2009 | 2004 Dodge Ram 1500

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