Mechanics

WHY IS MY ENGINE MISFIRING WHEN COLD?

2001 Ford Windstar • 6 cylinder FWD Automatic • 225,000 miles

My engine runs fine when it has had 5 - 10 minutes to warm up, but sometimes, not always, has rough idling and misfiring when the engine is started in the morning. I replaced the fuel filter because I did not see where it had been replace before and it was a cheap thing to try. I have tried to use iso-HEET and SeaFoam to help the problem, but nothing has proven to work. I would get codes, but the check engine light isn't blinking when I would be able to get to the store to check it. What are your thoughts? What's my next move?

I guess I really want to know if this is something I should just drop off to a shop or can I diagnose and fix on my own?
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Usfcire
June 25, 2012.




Has the engine light come on at all? Also my thought it get a can of mass air flow cleaner and clean the mass air flow unit. If the engine light has come on at all it should have set a pending code a good code reader will find it and then I can look it up and see if there is something we can check. Once the code it retrieved clear them.

Racefan966
Jun 25, 2012.
The codes are as follows: P0171, P0174, and P0303

The guy at the store asked when I last changed the plugs and wires, I would say 5 years or 130,000 miles maybe. The wires look great on the outside. I bought a socket for the plugs so I can pull them. But what do the codes tell you?

Tiny
Usfcire
Jun 25, 2012.
Everything if there is a code set. Ok with P0171 and P0174 that tells me the computer sees there is a lean and rich condition happening (mass air flow cleaning). P0303 tells me that cylinder number 3 is miss firing change plugs and ohm that plug wire get me the ohms and length of that wire ok.

Racefan966
Jun 26, 2012.
So change all plugs and maybe one wire, plus mass air flow cleaning. Where would I get at the mass air flow to clean it? Also, which cylinder is number 3? Sorry not sure about all that stuff.

Tiny
Usfcire
Jun 26, 2012.
Ok if you changed the air filter ever then that is where the mass air flow sensor is, the cleaner is available at your local parts store. Yes change plugs and maybe have to do plug wires should be all. It cylinder #3 that is miss firing is what P0303 means you have 6 cylinders so it should be the front one on the drivers side.

Racefan966
Jun 27, 2012.
I replaced all the spark plugs, I will clean the MAF sensor tomorrow. All the plugs were corroded and most were out of spec. I changed them out with the Bosch 4+ platinum plugs. Did not check the resistance of the wire, thought I would do the plugs and see if that works. The #3 is actually on the side of the engine facing the dash on the driver's side, and is was easy to get to, so if I still have issues, I will check that. Since they cleared the error codes, I have not had any issues, but it could be helped by the fact that the days have been so hot here in Kansas. Like I said it was happening once in a while and only in the morning. I will let you know how the MAF looks.

Do I just take out the air filter and intake hose and spray to my heart's content?

Tiny
Usfcire
Jun 27, 2012.
That right #3 is on the back side, sorry I knew that was thinking in backwards on how the engine is place in there sorry about that. Hasn't been so hot here in North Idaho. As for cleaning the mass air flow yes take out the filter spray it out and thats it. Anyway sounds like you will have fixed it if there is anything else just ask.

Racefan966
Jun 28, 2012.
Yeah all is well regarding the misfire, just started a small oil leak earlier this week, a few days after an oil change, not sure exactly where, but I know it is up high. Air Intake Manifold area so I am not sure if that is something I can fix or if I need that done by a professional.

Tiny
Usfcire
Jun 28, 2012.
If you have a mirror check the valve covers, check oil sending unit. The intake can leak oil out of the front or back of it but no where else really.

Racefan966
Jun 28, 2012.
The valve covers are good, what I am going to do is clean up the area and see where it is actually coming from. Is changing the intake manifold gasket tough?
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Tiny
Usfcire
Jun 28, 2012.

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