2000 Ford Mustang P0301 Code

BAIBBAS

MEMBER
2000 FORD MUSTANG
6 CYL
2WD
AUTOMATIC
185,000 MILES

I've got a P0301 Code on my 2000 Ford Mustang. It stands for cylinder 1 misfire. I've got new plugs, new wires, new coil pack, new egr valve, new egr valve regulator, new smog pump, new pre and post-cat oxygen sensors, MAF is new. My only two other options are new catalytic converter or new fuel injectors. The car runs rough between 40 and 50 mph. Any suggestions, I have the new injectors and plenum gasket. Prior to this I had the fuel system flushed out professionally as well. Help!

5 Replies

RASMATAZ

MECHANIC
75,992 POSTS

Check the compression and injector for that cylinder

Misfires can be caused by worn or fouled spark plugs, a weak spark (weak coil, bad spark plug wire), loss of compression, vacuum leaks, anything that causes an unusually lean fuel mixture (lean misfire), an EGR valve that is stuck open, dirty fuel injectors, low fuel pressure, or even bad fuel.

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Thursday, December 25th, 2008 AT 10:14 PM

BAIBBAS

MEMBER
3 POSTS

Check the compression and injector for that cylinder - Already done that, it's good

Misfires can be caused by worn or fouled spark plugs - Plugs are BRAND NEW, as are wires

A weak spark (weak coil, bad spark plug wire)- Wires, coil is BRAND NEW,

loss of compression- Compression is good,

vacuum leaks- No leaks

anything that causes an unusually lean fuel mixture (lean misfire), an EGR valve that is stuck open, dirty fuel injectors, low fuel pressure, or even bad fuel.- EGR valve and regulator is brand new.

It's either the injector or the Cat.

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Thursday, December 25th, 2008 AT 10:18 PM

RASMATAZ

MECHANIC
75,992 POSTS

Test the injector and backpressure of the exhaust system

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Thursday, December 25th, 2008 AT 10:22 PM

BAIBBAS

MEMBER
3 POSTS

Well, I've got brand new OEM injectors for the car and a new plenum gasket, so I was going to put all new injectors into it since I already have them and the injectors have 185K on them. This way if the problem is still persisting it's more than likely the Catalytic converter. It's the last thing on the list to check for a P0301 code.

I'd like to change out the injectors and plenum gasket myself, do you have any images/instructors I can use to do this? My Haynes manual doesn't help much with guidance to do this.

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Thursday, December 25th, 2008 AT 10:30 PM

RASMATAZ

MECHANIC
75,992 POSTS

A code P0301 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.