Why is my engine misfiring when cold?

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.

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?

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.

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...

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.

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?

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.

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.

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.

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?

depends upon your skills. I would be able to get you pics and torque specs and such.

okay, well I am back here again because the misfire things has come back, but this time while the engine is warm. I checked the codes and I still have a P0171, P0174, P0303, but now I also have P1518 which is maker specific and I read somewhere that it has to do with the intake manifold. I cleaned the area where the oil was leaking and the drip went away, but then earlier this week it came back with a vengeance. If you could help out this one last time I would appreciate it, I really want to do this myself, but I need a reliable car, and right now, I don't think I can drive the interstate, and that is the key for me to get home (I only go home on the weekends). Please respond ASAP so I can know if I should schedule my car for tomorrow afternoon at the shop.

Thanks.

Eric

Well P1518 is solved. I will report back to you after I take the van out for a longer drive on the highway. It should be Wednesday or Thursday. This is where I got my answer: http://www.youtube.com/watch?v=XcTVfrAgTLk

Ok P0303 is cylinder 3 missfire. It could be either a plug or plug wire so check them both. P0171 and 0174 could be because of the P0303 so fix that first.

Oh you went with bosch platinums that is why the missfire more then likely use autolite fine wire plugs. I have found that when I use bosch platinums I will have the car back with a missfire so I won't use them.

Just as a follow up, albeit very late, I have taken the van to a mechanic and the underlying problem were six ports nearly completely clogged up and potentially a faulty fuel injector. Once these were remedied, the van runs great. Thanks for the help!

That is great that it is fixed. Thanks for the follow up.