2002 P0301 OBD Code


2002 T-Bird with 17,000 miles. I have owned it about a month.
I had COPs and plugs replaced less than 500 miles ago with two year parts and labor warranty.
No problems for about a week then following problem started:
Engine misses just after start up, missing stops after driving about 30 seconds. No check engine light.
On next start up engine will miss just after start up, missing stops after driving about 30 seconds and Check Engine will illuminate.
I shut engine down and check codes. Will get P0301 code and clear code.
On next start up same process repeats even with engine still warm.
The 30 second missing seems to be on more than one cylinder. For you fly-boys, the missing is reminiscent of a radial aircraft engine starting.
I know that I could have a bad coil on cylinder one BUT my concern is;
Is there a problem other than ignition that results in P0301 codes ??
Can lack of fuel to injector system cause this code ?(low fuel pump pressure)?
Can fuel distribution or pressure to injectors cause this code ??
 
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biddle

Forum Moderator
Staff member
Cylinder 1 is misfiring, correct?
There are issues that will cause the COPS to repeatedly fail. In other words you replaced the effect of the problem, but not the cause of the problem. I suggest reading more in the COPS thread- You may also have a problem with your cowl seal, wiper seal etc, which is causing the coils to fail repeatedly! You can read more about that in this post.

I've seen people whining about it because of a bad design, etc but it's recurring because the underlying problem is not fixed in many cases.
 
When was the last time the coolant was changed ?
The anti-corrosion additives in the coolant have a life expectancy of a few years, such as 2 years for green, 3 for gold, etc. When the additives are used up electrolysis (from the variety of different metals used in vehicle engines and cooling systems) becomes a major problem and starts eating the metals. The result is dirty looking coolant that soon becomes rusty looking coolant and then the various components start to leak or perform poorly. Lubricating additives are depleted as well as many others. Distilled water and de-ionized water is better than clean drinking water extending the useful life of the coolant, but regular replacement of the coolant is best.
 
No evidence of moisture, oil, or anti-freeze. No rain or car washes between replacing COPs and problem starting.
I am going to have that coil replaced next week but I suspect that the P0301 code is not reflecting the real problem.
 
take and swap the number 1 coil with the spark plug with another cylinder and clear the code. see if you get a new code when you start up showing that other cylinder number and not number 1, then you know it's the coil or plug.
 
Flash and I both suggest that you diagnose first Before throwing parts at it. You can swap coils easily enough.. If you find the other cylinder is misfiring then its most likely the coil. If you have the same result then chances are you'll be digging into that engine ....
By chance is there white smoke on start up ....? could be a leaky head gasket........ Gummed up fuel injector ......... Rodent eaten wiring .......
The next step could be a cylinder balance test. If your guy has the proper test equipment .....
 
All COPS and plugs were changed last week. P0301 code was occurring before I had them changed, that is why I had COPS/Plugs replaced.
P0301 code continues to appear after COPS and plugs were changed. That is why I am asking if anyone on this forum is aware of any engine condition that will cause this P0301 code OTHER than a COPS/Plug problem.
 
Burnt valve ..... Leakey head gasket , Carbon deposit on the valve seat......... Vacuum leak..... Clogged injector ......PCM ........ wiring ........
You need a cylinder balance test and a compression test, and possibly a cylinder leak down test.....

Cars that sit for long periods of time can have fuel issues ......... Refer to the valves in these pictures.... 12 bad valves seats with burned on carbon deposits. Poor fuel quality or stale fuel.

Cars need to be driven and my suggestion is to use only Top Tier Fuels.
 

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BUT you said ,
"I had COPs and plugs replaced less than 500 miles ago with two year parts and labor warranty.
No problems for about a week then following problem started: "

So did you have a problem before the COP's and plugs changed? YES.

did the problem stop with new parts? YES. so maybe your new parts have failed.

have you gone back to the shop that put in the part?
 
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