More info on my misfire issue

[captinsho]

I posted a message about a misfire issue I have been having and got a lot of good feedback... however I left out a VERY important bit of info. When the engine is coldl, and when I say cold I am taking Michigan below freezing temps, the engine runs great. This will only last for 1/2 to 1 mile and by then it is warm enough that it runs poorly again. But at first when it is very cold it has sooooo much power it isn't funny. I can hammer the petal and it does not misfire once. This became very obvious to me yesterday and I thought I would post this. I am wondering if this could be due to that faulty air charge sensor that the Ford dealer found? Maybe the car is running to rich and that will cause the misfire when it is warm but allow it to run good when it is very cold. Any ideas? If this is a possiblity would someone know how to test it?

 

[Mr Anonymous]

Driving a cold engine hard will send it to an early grave.

 

[sdpatt]

SHOooo:
Driving a cold engine hard will send it to an early grave.

What he said.

You apparently have a heat related failure in an electrical component: plug, plug wire, sensor, etc. If you keep hammering on a cold engine, it won't matter if you fix the misfire, the bearings will be shot.

 

[EZ4U2ENVY]

I have the exact same issue stil trying to find the problem. its very irritating but one thing i dont do is drive it cold- reason being no lubrication lots of friction- problems in future. i think the cause would be coil- wires - spark plugs. these are the most cause for misfireing of hesitation-

Unless your running very rich than you got o2 sensors and act and ect sensors

which you running rich is a quite possibly because in a cold state the car will run faster.

this might not help you but if i find the problem of my situation ill let you know

 

[captinsho]

I am very aware of the hazards of running a cold engine hard. The only reason I did it was becuase as I pulled away from my house it did not act like it was hesitating. I hammered on the gas to see if doing this would cause a misfire... hoping to see in what conditions the car was misfiring. It did not misfire at all. Once the engine was warm and fully lubricated I did it again and then it did misfire. It is absolutely not something I would make a habit of but I do think doing this helped me find another condition to my problem. sdpatt, do you have suggestions on how to test and eliminate to find my problem... if it is electrical? Do you have any input on what EZ4U2ENVY said about the O2 sensors? I have the testing procedures from Shotimes and plan to test them ASAP. What is your feeling on the electrical. I tested both of my coil packs (have a spare from my old roommates 94 MTX) a couple of months ago when the problem started and they came out in range. EZ4U2ENVY I would LOVE to hear if you find a solution to your problem. Even if it is not the exact same problem I am having it will at least give me a route to try. Thanks for all of you guys input so far... I do appreciate it.

 

[AutoSHO]

Could be the Engine Coolant Temp Sensor. Got a Check engine light? You may want to pull the codes, or re-iterate them if you already have.

Sounds like a bad catalytic convertor if I had to guess.

 

[captinsho]

Bad cat... realy. No one has mentioned that. Why would that cause such an extreme misfire issue? I have a high flo 2-1/2" dia cat w/2-1/2" pipes. Would this cause a problem? I have had this set up for over a year while it worked fine.